Step 1Cut the bread into slices and place in a shallow bowl. Cover the bread with water and allow it to soak until fully saturated, about 3 to 5 minutes. Remove the bread and gently but firmly squeeze out the water. Shred the bread by gently pulling at the pieces with your fingers. Place in a large serving bowl.
Step 2Dice the onion. Peel the cucumber and cut it in half lengthwise. Scrape out the seeds with a spoon and dice. Dice the tomatoes by cutting them first into 8 wedges, then slicing the wedges in thirds. Add the tomatoes, cucumber and onion to the bread. Tear the basil leaves into pieces and add to the bowl.
Step 3Place the oil and vinegar in a small jar, cover and shake to combine. Season the dressing with the salt and pepper to taste. Pour the dressing over the salad and toss thoroughly. Adjust seasonings with salt, pepper or vinegar to taste. Serve at once or allow to stand at room temperature, covered, up to 2 hours.