Cook pasta in 8-quart pot according to package directions; drain. Keep pasta hot.
Brown meat in 6-quart pot over medium-high heat. Season with salt and pepper, if desired; drain. Add onions; cook until tender. Stir in spaghetti sauce and undrained tomatoes; cook 5 minutes, stirring occasionally. (Pour half of sauce into freezer container; cool, cover and freeze for another meal.).
Add zucchini to remaining sauce; cover and cook over medium heat 7 to 10 minutes or until zucchini is tender. Serve sauce over hot pasta. Sprinkle with grated Parmesan cheese and garnish, if desired.