Place first seven ingredients in large bowl. Mix thoroughly with your hands just until combined. (I wear food prep gloves.) Shape into approximately 30 1-inch balls.
Bake in an ungreased oblong pan (13x9x2) in a 400°F oven until light brown, 20-25 minutes. OR: microwave meatballs in an ungreased baking dish, 6 minutes on High, turning once. OR: cook over medium heat in frying pan, turning occasionally, until brown, about 20 minutes.
Place cooked meatballs and spaghetti sauce in crock pot. Cook on low for about 2 hours. If you cook longer, stir every hour or so.
Place meatballs and sauce in buns/rolls and top with mozzarella cheese.
Note, I microwave the meatballs to cook them.
(A friend places the raw meatballs & sauce in the crock-pot and cooks them for 8+ hours on low, but I have never tried this.).