there are a lot of tools you will need.that being said , there are a lot you already have around the house.you will need a good knife.those razor knifes you get at homedepot the little plastis orange ones.you can use spoons and kitchen knives and other things.
using the razor knives, be careful or you will cut through the skin.if you can get a veido and see what they use and you will see what you need.
there is not enough space to tell you all you will need in the futher.

good luck,one thing,if you mess up on the squirrel you can always get another.