Why skin them? That is where a lot of the good stuff is. Or skin them but blend up the skins and kick them back into the sauce. I will never peel a potatoe. Never have. Dittos for tomatoes
Yes, there are a lot of vitamins in the skins. I do the same thing with apple skins when making Apple Crisp. I put the peeled skins in my food processer and then sprinkle over the apples before adding the crumble topping.