Just read that canning pears with the skins on improves the flavor, the skins slide off easily later if you don't want to eat them, and it cuts prep time by a lot!

Yes, it works fine.  The skins get soft, and are quite tasty.

I'm pretty sure both pear and apple skins won't come off unless you peel them.
I think  the skin's a vital part of organic fruit.

Is it safe? Canning tends to be something that you aren't supposed to improvise on.

Yes, the skins will peel off quite easily after canning, much like peach or tomato skins peel off after blanching.

And yes, it is safe to can them with the skins on.  Peeling peaches, pears, and the rest is a cosmetic choice.  The acidity of the fruit is sufficient for it to be safe.  If you were worried about it, though, you could add a teaspoon of lemon juice to each jar, to be sure.