Brush first 6 ingredients with oil; sprinkle evenly with black pepper and salt. Place bell peppers on a grill rack coated with cooking spray; grill 5 minutes. Add eggplant; grill 5 minutes. Add asparagus; grill 5 minutes. Add zucchini; grill 5 minutes. Add tomatoes; grill 5 minutes or until all vegetables are tender, turning vegetables as needed. Remove vegetables from grill. Cut each bell pepper into quarters; cut eggplant halves and zucchini halves each into 4 equal pieces. Serve vegetables with Ranch Dressing.