2 c. tuna, chunk style
2 c. boiled potatoes, diced
1/2 c. celery, chopped fine
1 tbsp. onion, chopped fine
1/3 c. French dressing (low calorie cream style works great)
1/2 c. Miracle Whip salad dressing

Combine all ingredients. Mix well. Line around edge of oblong dish with lettuce, add tuna mixture, then place 1/2 slice of tomato between lettuce leaves and tuna (tomato is optional). Serve cold.