4 cups day old (somewhat dry and hard) crusty bread (Italian or French loaf), cut into chunks the same size as the tomatoes*
1 cucumber, skinned and seeded, cut into large chunks
1/2 red onion, chopped
1 bunch fresh basil, torn into little pieces
1/4 to 1/2 cup good olive oil
Salt and pepper to taste
* If you don't have hard old bread sitting around, you can take fresh crusty bread, cut it into big cubes, lay the cubes out on a baking sheet, and put in a 300°F oven for 5-10 minutes, until the outer edges have dried out a bit (not toasted, just dried). If you use fresh bread without doing this, the bread may disintegrate into mush in the salad.
Mix everything together and let marinate, covered, at room temperature for at least 30 minutes, up to 12 hours. Do not refrigerate or you will destroy the texture of the tomatoes. Serve at room temperature.