Using a peeler on Yom Tov
The use of a peeler on Shabbos is subject to the Borer prohibition, and is thus prohibited to be used on Shabbos to remove inedible peels, and with some Poskim prohibiting it entirely even to remove edible peels. [See Topics in Practical Halacha Vol. 2 O.C. Halacha 42] The question is thus raised regarding its status on Yom Tov and whether a peeler may be used indiscriminately.
The laws of Borer on Yom Tov: The laws of Borer on Yom Tov differ from that of Shabbos, at times retaining the Shabbos restrictions while at others receiving a new set of laws relating to its form of separation. The following is the general rule: Those foods of which it is common to separate their waste many days in advance, and hence have the food placed in storage for future use, such as flour and grains, retain the same Borer restrictions as Shabbos, and hence one may only remove the good from the bad with one’s hands for the sake of right away use. Furthermore, even those foods of which it is common to separate their waste on the same day as their use, if one could have separated the waste before Yom Tov, they retain the same Borer restrictions as on Shabbos. If, however, one was unable to separate the waste before Yom Tov, then one is to separate the waste and food in the method that will be least strenuous. In such a case, it is permitted to separate in the above mentioned method even through using a vessel and even for non-immediate use, so long as it is done for the sake of eating on Yom Tov. However one may not use professional Borer vessels such as a sieve and sifter, which are used for separation of many days’ worth of food. [However, some Poskim rule it is forbidden to use any professional Borer vessel on Yom Tov that is commonly used during the week, even if it is not commonly used for separation of many days’ worth of food. The practical ramification between these two approaches is regarding whether a peeler may be used on Yom Tov, as will now be explained.]
It is permitted to use a peeler on Yom Tov to peel any food of which its quality and freshness would be diminished if it were to be peeled before Yom Tov. This applies even if the peel is inedible, and certainly if the peel is edible. The foods may be peeled even for non-right away use, so long as the intent is for it to be eaten on that day of Yom Tov. However, those foods which could have been peeled before Yom Tov without it causing any diminishing in freshness or taste, may not be peeled using a peeler. Practically, almost all fruits and vegetables which are peeled some time prior to being eaten lose their freshness and are hence included within this allowance. Nonetheless, some Poskim are stringent and rule that one is not to use a peeler on Yom Tov just like on Shabbos.
It is permitted to use a peeler to peel foods on Yom Tov without restriction, so long as one’s intent is to eat the food on that day of Yom Tov and one would not have desired to already have peeled it before Yom Tov due to it becoming diminished in freshness or taste.
 See Rama 321:19, Admur 319:9, M”B 319:22 and 24; Shabbos Kehalacha Vol. 2 p. 294 and 299-307; Piskeiy Teshuvos 321:34-35
 Iglei Tal Borer 6; Ketzos Hashulchan 125:16; Piskeiy Teshuvos 321:35
 M”A 321:19 regarding apples; Elya Raba 321:30; Tosefes Shabbos 321:41; M”B 321:84; Orchos Chaim 319:22 in name of Meorei Or; Igros Moshe 4:74 Borer 8; Az Nidbaru 9:10; Chut Shani 25:7
Other opinions: Some Poskim rule that fruits and vegetables which majority of people eat together with the peel, may be peeled using a peeler, and may even be peeled for later use, on Shabbos. [Peri Megadim 321 A”A 30, brought in Shaar Hatziyon 321:97; Iglei Tal Borer 6:12; Shevisas Hashabbos Borer 24 and footnote 45; Kaf Hachaim 321:141; Ketzos Hashulchan 125:16 [see however Ketzos Hashulchan 126 footnote 19]; SSH”K 3:34]
 The reason: As a peeler is the normal vessel used to remove the peel from a fruit/vegetable and hence is similar to a sieve and sifter, which is Biblically forbidden to be used. [See Admur 319:1; M”B 319:2; Rashi Shabbos 74a] Some Poskim hold that the separating prohibition applies to even edible peels and thus when peeling it one must abide by all Borer restrictions, which include not peeling it with a peeler, and even when using a knife, to only do it for right away use. The reason that even edible peels contain the Borer restriction is because when they are peeled off, they are generally thrown out, and hence have a status of Pesoles when one comes to peel it. [Piskeiy Teshuvos 321:34]
 See Admur 506:4; 510:3-6; Michaber 510:2; Beitza 14b; Nitei Gavriel 5:9; Piskeiy Teshuvos 510:1
 Admur 506:4 regarding flour; 510:3; Beitza 29b; Shita Mekubetzes Perek Gimel in name of Ramban; Ritva Megillah 7b
 Admur 510:5; Taz 510:3
 Admur 510:3-5; Michaber 510:2; Beis Hillel in Mishneh Beitza 14b and Braisa ibid
How to separate: If there is more food than waste and it is easier to remove the waste, then one is to remove the waste. However, if there is more waste than food, then one is to remove the food, even if it is more troublesome to do so. [Admur 510:4; Michaber ibid; Braisa ibid]
 Admur 510:3; Michaber and Rama 510:2
Other opinions: Some Poskim rule that all Borer that is Biblically forbidden on Shabbos is likewise forbidden on Yom Tov. [Rashba Shabbos 138a and Avodas Hakodesh 2:5]
 Admur 510:2 and 6; Michaber 510:1; Beitza 14b
 Admur 510:2; Rashi Beitza 12b that using a vessel designated for bulk separation involves Uvdin Dechol; Ran Beitza 6a; Maggid Mishneh 3:15; Biur Halacha 510:4 “Mutar”; Piskiey Teshuvos 504:1; Nitei Gavriel 5:6
 Chayeh Adam 82:2; M”B 510:12, however, see there 510:7 and Biur Halacha ibid
 Implication of Admur 510:2-3; Rav SZ”A in SSH”K 4:27; Beir Moshe 8:203; Chut Shani 16; Hilchos Chag Bechag 5 footnote 23 in name of Rav Elyashiv; Or Letziyon 3:19-7; Piskeiy Teshuvos 504:3; Nitei Gavriel 5:14; See Yom Tov Kehilchaso 8:15 p. 204 and footnote 42
 The reason: This follows the ruling of Admur that all foods from which one was unable to separate its waste before Yom Tov is permitted to be separated on Yom Tov even through using a vessel and even for non-immediate use [Admur 510:3], so long as the vessel is not typically used for bulk separation [Admur 510:2].
 See Poskim ibid who permit peeling edible peels from produce even on Shabbos
 Yom Tov Kehilchaso ibid footnote 42
 Implication of Chayeh Adam ibid and M”B 510:12; Shvus Yitzchak Inyanei Yom Tov 9 in name of Rav Elyashiv, unlike Hilchos Chag Bechag ibid; Ruling according to Rashba Shabbos 138a and Avodas Hakodesh 2:5 who forbids on Yom Tov all Borer that is Biblically forbidden on Shabbos. See Iglei Tal Borer 6