Schmalz is simply lard, or in Jewish usage, I believe, chicken fat. It you render lard, the cracklings are the delicious little bits of browned meat or rind that float up. Mix them in corn bread for that old-fashioned flavor. (Try to find a recipe for cracklings in modern cookbooks!) Likewise for rendering beef suet, if only a few steak trimmings -- delicious little dabs of pure calories for your potatoes. Likewise for rendering chicken skins.
The pioneers preserved pork and other meats over winter simply by immersing them in a barrel of lard. That technique probably came from the old world, and it may have been a "dish" to serve the greasy meats from the lard barrel. But who knows? I'm out of guesses.