Cooking tip: When cutting the iceberg lettuce, take care to leave the core intact. This will help keep the leaves together so they won’t fall apart on the grill. For an extra special touch, throw a handful of soaked wood chips onto the coals 5 minutes before grilling. —Healthline
Whisk together first three ingredients. Set aside.
Cut lettuce in half and each half into 3 wedges. Lightly spray with cooking spray and grill over medium direct heat, 1 minute, turning once. Place 1 wedge on a plate, drizzle with dressing and sprinkle with tomatoes and chopped chives. Serve immediately.