Prepare broiler or grill pan.
Combine first 9 ingredients. Divide lamb mixture into 4 equal portions, shaping each into a 3/4-inch-thick patty. Place patties on broiler or grill pan coated with cooking spray. Cook 4 minutes on each side or until done.
Line bottom half of buns with lettuce leaves. Top each with 1 tomato slice, 1 patty, and top half of bun.