Brush corn with oil. Grill corn, covered, over medium heat 10-12 minutes or until lightly browned and tender, turning occasionally. Cool slightly.
Cut corn from cobs; transfer to a small bowl. Stir in salt, pepper and pepper flakes. In a 2-qt. glass bowl, layer a third of each of the following: corn, tomatoes, onion and basil. Repeat layers twice. Pour dressing over top; refrigerate at least 1 hour.