Combine all ingredients except lettuce and green onions in a bowl.
Refrigerate overnight; stir occasionally.
Drain shrimp, reserving marinade. Broil shrimp 4 inches from heat until
cooked and tender (about 2 minutes on each side, less for small shrimp). Do
not overcook or shrimp will become tough. Brush occasionally with marinade.
Serve shrimp on shredded lettuce; sprinkle with chopped green onion.