Position oven rack 4 to 6 inches from broiler; preheat broiler. Stir together tomato sauce and tomato paste in large skillet. Add meatballs; cover. Heat over medium-high heat 10 minutes or until meatballs are hot, stirring occasionally.
Meanwhile, place rolls on baking sheet; broil 1 minute or until toasted lightly.
Place 4 meatballs with sauce on each roll. Top each with cheese. Broil just until cheese melts. Serve immediately.