HEAT grill to medium heat.
COOK pasta as directed on package.
MEANWHILE, mix 1/4 cup dressing and 1/3 of garlic. Thread shrimp onto 6 skewers; thread 24 tomatoes onto 6 additional skewers alternately with bread. Grill all skewers 3 min., turning and brushing occasionally with half the dressing mixture. Remove tomato skewers from grill. Place onions in single layer on grill grate. Grill onions and shrimp 2 to 3 min. or until shrimp turn pink and onions are crisp-tender, turning and brushing occasionally with remaining dressing mixture.
DRAIN pasta; place in large bowl. Quarter remaining tomatoes. Add to pasta with remaining dressing, garlic and basil; mix lightly. Slice onions; stir into pasta mixture. Sprinkle with Parmesan. Serve with shrimp skewers.