CHOP enough cilantro to measure 1 Tbsp.; set aside. Blend dressing, remaining cilantro and garlic in blender until smooth.
COMBINE 1/2 cup dressing mixture with cherry tomatoes, tomatillos and onions.
ARRANGE tomato slices on large platter; drizzle with remaining dressing mixture. Top with basil, reserved cilantro, cherry tomato mixture and cheese.