Cut a 3/4-inch slice off the stem end of each tomato; reserve the tops. With a spoon, carefully scoop out the pulp and discard. Sprinkle the inside of the tomatoes with salt
and place the tomatoes upside down on paper towels to drain for 1 hour.
In a medium bowl, mix together the capers, pine nuts, parsley, oregano, olive oil, and lemon juice. Add the flaked tuna and mix together gently. Season to taste with salt and pepper.
Sprinkle the inside of the tomatoes with pepper. Distribute the tuna evenly among them, cover with the reserved tops, and serve.
NOTE: These stuffed tomatoes can be made several hours in advance and refrigerated; bring to room temperature before serving.
Makes 6 servings.