Is allowed to be eaten from the letter of the law, but the custom in these provinces is to not eat even on the last day of Yom Tov, Kitniyos [which have gotten wet with water. Dry kitniyus which has not gotten wet, may be eaten.]
The reason behind this custom is because if kitnoyos were to be allowed to be cooked and eaten then the laymen would come to think that even wheat/spelt/rye/oats/barley kernals is permitted to be cooked and eaten.
May one own and get benefit from kitniyus?
One may both own and benefit from kitnyus on Pesach even if it is wet, as it was only forbidden in eating when wet.
May one have kitniyus products on ones table when one eats?
One may [have Kitniyus products on ones table, such as to] have kitniyus oil on ones table which is being used for candles. The reason for this is because we do not suspect that the oil will fall into food, as even if it does it is nullified in majority.
What is the Halacha if kitniyus fell in ones food?
It is nullified in majority as this prohibition due to custom is a mere stringency. [See Q&A]
The definition of Kitnoyos:
Legumes: Based on the reason mentioned above, only legumes are forbidden due to the custom, being that they are similar when cooked, to the cooking of the 5 grains.
Seeds: However seeds are not forbidden according to the custom, being that they are not similar to grains. This however is with exception to mustard being that it grows in stalks similar to legumes. And with exception to cumin which is similar to wheat. However cumin which is not similar to wheat, there is no custom to forbid.
Vegetables: All types of vegetables may be used as they are not similar to grains.
What are some examples of Kitniyos? [Corn], Rice, [Buckwheat], beans [including soy], lentils, sesame, mustard, Millet, [chickpeas], [Peas], [String beans], [grouts, sun flour seeds, poppy seeds, cloves, fenugreek, green beans, cumin, caraway, linseed, cardamom, coriander, fennel] Many legumes and seeds are considered Kitniyus the following is a short Kitniyus list: Anise, ascorbic acid, aspartame, beans (all types of beans e.g., kidney, lima, garbanzo), bean sprouts, BHA and BHT (in corn oil), black-eyed peas, buckwheat, calcium ascorbate, canola (rapeseed) oil, caraway, citric acid (sometimes Chametz), chickpeas, coriander, corn and corn oil, corn syrup, cumin, dextrose, emulsifiers, fennel, fenugreek, flax seeds, glucose, green beans, guar gum, hydrolyzed vegetable oil, kasha, kimmel, lecithin (all commercially produced lecithin is made from soy), lentils, licorice, Lucerne, lupine, maltodextrin (sometimes Chametz), millet, MSG (can be from beets [kosher for Pesach], corn [kitniyos], or wheat [Chametz]), mustard and mustard flour, NutraSweet, peanuts, peas, polysorbates (sometimes Chametz), popcorn, poppy seeds, rice, saffron, sesame seeds, snow peas, sodium citrate, sodium erythorbate, sorbitan, sorbitol (could be Chametz unless manufactured in the U.S.A), soybeans and soy oil, stabilizers, starch (possibly Chametz), string beans, sunflower seeds, tofu, vitamin C (could be Chametz), xanthan gum (may be Chametz). Quinoa is disputed if it is Kitniyos. Flax seeds and hemp seeds are technically not kitniyos. However since they can be ground as flour, some opinions include them in the category of kitniyos.
May one eat Kitniyos on Erev Pesach until the night?
Some Poskim rule it is permitted to eat Kitniyos on Erev Pesach until the night on the condition that one checks the kernels for grains three times. However other Poskim rule that eating kitniyos is forbidden starting from the 5th hour. Practically the widespread custom is to be stringent.
May children or an ill person eat kitniyos?
If needed they may be given kitniyos to eat, even if there is no danger involved. When doing so it is proper to designate pots which will be used for the kitniyos.
May one cook in a pot that had kitniyus cooked in it?
After 24 hours one may cook in it even lechatchilah. Within 24 hours one may not do so, although if does then the food is permitted as there is majority of heter verses the kitniyus taste.
If an Ashekenazi woman married a sefardi may she eat kitniyos?
Yes she may and she does not even need to do removal of a vow.
Is Kitniyos Muktzah on Yom Tov of Pesach?
May one eat Kitnoyos on Shabbos which follows the last day of Yom Tov?
It is permitted to eat edible Kitniyus on Shabbos which follows the last day of Pesach. Thus one may buy Chumus and Tehina which are Kosher for Pesach during Chol Hamoed, and eat it that Shabbos.
May one cook the Kitniyos on Friday which is Yom Tov?
May peanuts be eaten?
The Igros Moshe writes that from the letter of the law peanuts are permitted to be eaten, although in places that the custom is to be stringent one may not permit them to eat it. [To note however that the Niteiy Gavriel writes plainly that Peanuts are kitniyus and does not make mention of the Igres Moshe]
May coffee and cocoa be eaten?
It is allowed as it grows on a tree and is thus not considered kitniyus.
However there are those which are stringent to not eat it, in order so others do not think that kitniyus is also permitted to be eaten.
The Chabad custom: Boiling in water before Pesach.
Are Potatoes and potato flour allowed to be eaten?
Some opinions prohibit using potatoes flour being that it is too similar to grains and an ignoramus may come to permit even flour of grains if it were to be allowed. The Chayeh Adam even goes as far as saying that even actual potatoes are forbidden. The custom however is to be lenient even regarding potato flower, and so rule majority of the Poskim.
May Kitniyus Shenishtana/Kitniyus oil be used?
Some Hashgacha organizations allow kitniyus derivatives to be used in their Kosher Lepesach labeled products. An example of this is corn syrup and aspartame, which is a sweetener used in diet sodas.
Other Hashgacha organizations, such as Rav Landaus, do not accept any kitniyus derivatives, and thus there is no Kosher Lepeasach diet coke in Israel.
Opinion of Admur: From the fact that Admur considers Kitnityus oil to be forbidden to eat implies that he holds that all kitniyus derivitives are forbidden.
May one use canola/soy oil, and other oils made of seed?
Many Poskim allow oil made from seeds to be used if they were carefully checked. However the Minchas Yitzchak prohibits all oils made from seeds being that it is difficult to clean them from grains.
 And so rules Michaber 453/1, and thus Sefardim allow it to be eaten. However even they must be careful to check the legumes for grains beforehand.
 The Mahril writes that one who goes against this custom is Chayiv Misah as he has gone against a Rabinical Mitzvha.
However there are opinions which prohibit kitniyus to be eaten even when dry and raw. [Piskeiy Teshuvah]
However the M”B/Taz lists other reasons: The Taz says that “the Tur writes its because wheat gets mixed into the kitniyos. The smak writes that the reason is because one can make flour/dough out of the legumes and thus one may come to mix it up with chameitz flour/dough and come to allow even chameitz flour/dough. [Taz 453/1]
 Aruch Hashulchn
 In the gemarah Rav Yochanan Ben Nury holds that rice is considered chameitz, while the sages argue. The Poskim rule like the sages.
 R. Blumenkrantz
 R. Blumenkrantz
 R. BlumenkrantzVetzaruch Iyun if according to Admur these things are kitniyos, as they are really seeds and not legumes.
 Piskeiy Teshuvah
 P”M 444 A”A 2; The peri megadim allows it to be eaten until the night of the 15thif one checks the kernels three times.
 Chok Yaakov 471/2; Daas Torah 453
 Sheivet Halevi 3/31
 Piskeiy Teshuvah, based on M”B 107
 Piskeiy Teshuvah
 R. Blumenkrantz in name of Igros Moshe and Minchas Yitzchak
 So is apparent from all the early and late Achronim mentioned in Minchas Yitzchak 7/33 which do not mention it as being Muktzah.
Other Opinions: The Minchas Yitzchak ibid brings that according to some opinions Kitniyus is Muktzah on the Shabbos directly following Pesach being that it was set aside by Bein Hashmashos from being eaten. Vetzariuch Iyun Gadol based on all explained above.
 As it is edible for Sefaradim, and is hence similar to wine of a Nazir.
 Yechaveh Daas 2/64; See Admur 310/4; and so is apparent from all the early and late Achronim mentioned in Minchas Yitzchak 7/33 which do not mention it as being Muktzah.
Reason it is not Muktza:
- Edible Kitniyos is not Muktza on this Shabbos, despite it being inedible during Bein Hashmashos, as it is similar to a cow which was slaughtered, that as soon as its prohibition leaves it is permitted, and only by those things which were pushed away with one’s hands and thus became Muktzah [such as candles/esrog/ dried grapes] do they remain Muktzah even after their reason of Muktzah has left. [Admur ibid; M”B 318/8]
- Furthermore, even if one were to argue on the above premises it is ruled that an item which was Muktzah on Bein Hashmashos because of the previous day we do not rule it remains Muktzah for the rest of Shabbos. [665/1]
- Furthermore, even on Yom Tov itself Kitniyus is not Muktzah as it is edible for Sefaradim, and is hence similar to wine of a Nazir.
Other Opinions: The Minchas Yitzchak 7/33 brings that according to some opinions Kitniyus is Muktzah on the Shabbos directly following Pesach being that it was set aside by Bein Hashmashos from being eaten. Vetzaruch Iyun Gadol based on all explained above.
 See Minchas Yitzchak 7/33 for a thorough analyses on this topic.
 Bircheiy Yosef; Sdei Chemed Chameitz Umatza 6/6; Luach Rav Tuchinsky
Reason: As the Kitniyos is available for Sefaradi guests to eat. This is similar to Chalah in Chutz laarezt which may be baked on Yom Tov if there is a Tahor Kohen available. [Admur 467/20-21]
 Kneses Hagedola 62; Minchas Yitzchak ibid and other Poskim mentioned there
- As it is similar to a person fasting which is forbidden in cooking anything even for others.
- As one may come to eat it
 Piskeiy Teshuvah
 Piskeiy Teshuvos 453/
 Shaareiy Teshuvah 453/
 Piskeiy Teshuvah
 Piskeiy Teshuvah