COAT grill grate or broiler pan with no-stick cooking spray. Heat grill or broiler.
TOSS tomatoes with basil, salt, pepper, vinegar and oil in medium bowl. Let stand 10 minutes to blend flavors.
SPRAY both sides of bread slices with no-stick cooking spray. Sprinkle with salt and pepper. Grill about 5 minutes, turning once, or just until bread is lightly browned and crisp.
TOP with tomato mixture. Garnish with fresh basil leaves, if desired.