Serves 4 as an entrée.
2 heads lettuce
8 large, very ripe tomatoes
1/4 cup finely chopped white onion
1/4 cup bread crumbs
12 oz. drained flaked tuna
1 cup seeded and minced cucumber
Tear lettuce into bite-sized pieces, wash & spin dry enough lettuce to make a thick bed on your dinner plate. Wash tomatoes. Slice a very thin section of the bottom (blossom) end so the tomato will sit flat. Slice the top off the stem end. Using a spoon, hollow out the tomato, saving the flesh that you can take out. Break any juice pockets that you find and remove seeds. Lightly salt the inside of the hollow tomato and turn it upside down on a plate to drain while you prepare the filling.
Finely chop the reserved insides of the tomato and add onion, tuna, cucumber and bread crumbs. Stir in just enough mayo to moisten and bind the filling. Place tomatoes on bed of lettuce. Spoon filling into tomatoes, allowing extra filling to spill over onto lettuce. Serve at once.