In a large bowl, toss the bread cubes with 2 tablespoons of the basil olive oil and season with salt and pepper, to taste. Arrange on a baking sheet and bake for 5 minutes, then toss the bread cubes and bake until golden, another 3 to 5 minutes. In a small saucepan, over low heat add the balsamic and simmer until reduced by half.
Cut the smaller tomatoes in half, quarter the medium tomatoes and slice the larger tomatoes. Cut the cucumber, lengthwise in half, and slice it into half moons or dice it into cubes.
In a large serving bowl, mix the tomatoes, cucumbers and remaining oil and season with salt and pepper, to taste. Add the bread cubes and toss. Drizzle with the reduced balsamic and serve.