1/4 cup plus 2 tablespoons olive oil
3 large beefsteak tomatoes, cut into 3/4-inch dice (about 4 cups)
1 cucumber, peeled and cut into 3/4-inch dice (about 2 cups)
1/4 cup loosely packed fresh basil, torn into bite-size pieces
1 tablespoon red-wine vinegar
Salt and pepper
Heat grill to medium. Brush bread slices on both sides with 2 tablespoons oil. Grill until lightly charred on both sides, 3 to 4 minutes. Let cool slightly, then cut into large cubes.
In a large bowl, toss bread cubes with tomatoes, cucumber, and basil. Drizzle with vinegar and remaining 1/4 cup oil, and season with salt and pepper. Toss to combine, and serve.