Combine ground beef, Parmesan cheese, bread crumbs, water, egg, garlic and salt in medium bowl; shape into 12 meatballs.
Bring Sauce to a boil over medium-high heat in 3-quart saucepan. Gently stir in uncooked meatballs.
Reduce heat to low and simmer covered, stirring occasionally, 20 minutes or until meatballs are done. Serve over hot spaghetti and sprinkle, if desired, with Parmesan cheese.