Peel the cucumbers and cut them into half-inch cubes. Add the onion, lemon juice, butter, water and seasonings to taste. Simmer for five minutes.
Remove the seeds and pulp from the tomatoes and drain them. Fill the tomatoes with the cooked cucumber mixture. Sprinkle with bread crumbs. Bake for about ten minutes, until the tomatoes are tender and the crumbs are brown.