The Halacha permits peeling fruits and vegetables on Shabbat. Even though, in general, the laws of Borer do not allow removing the Písolet (the peel) from the Ochel (food), in this case it is permitted since there is no other way to access the food. Nevertheless, the peel may be removed only immediately prior to the meal or the consumption.
The Poskim discuss whether foods with wrappers have the same Halacha as foods with peels. That is, would it be prohibited to remove the wrapper well in advance of consumption, as with peels?
Rabbi Shlomo Miller in his new Sefer, Shabbat Shel Shlomo, distinguishes between peels and wrappers. A peel is an integral part of the fruit and grows with it, whereas the wrapper is an external covering of a food that was already edible in its original state. Therefore, taking off the wrapper is not a Tikun of the food and may be removed well in advance of consumption.
However, he cites Poskim who distinguish between different types of wrappers and view tightly bound wrappers, such as the plastic around string cheese or salami, as a peel. Such wrappers should only be removed for immediate use. Other wrappers, such as bags of potato chips, do not have the status of a peel and may be opened well in advance of consumption.
Tight wrappers may be removed from food only immediately prior to consumption.