Combine first 4 ingredients; cover and chill 30 minutes.
Combine meat and next 4 ingredients; divide mixture into 8 equal portions, shaping each into a 4-inch patty. Broil 4 minutes on each side or until done.
Place a lettuce leaf on bottom half of each bun; top each with a patty. Top evenly with tomato mixture, and cover with bun tops.