Wash and dry 8 small, firm tomatoes. Cut off tops about 1/4 of the way up and scoop out most of the pulp, leaving a little around the walls so tomatoes retain their shape. Invert tomatoes cut side down to allow moisture to drain (for about 30 minutes). 

Fill tomatoes with salad of choice, so it protrudes about 1/2 inch. Replace top tomato slices, arrange tomatoes on lettuce-lined serving dish, and chill 1-2 hours.