It reminds me of the German phrase "Haut und Haar"
I guess skinn means hide or leather?
Yes, it's used for the skin of an animal, and for the outer layer of some fruits (if the fruit is hard or can be easily peeled, we call it 'skall' instead) and berries.
You'll also see it in some fixed expressions and sayings referring to humans.
Epler would have "skinn", right? Because in Swiss German, we distinguish between Schinnti and Schale, with apples having the former.