Submerge the slices of day-old Tuscan-style bread in a bowl of water.
Use your hands to squeeze out all the water that the bread has absorbed. Break up the bread into small pieces and put into a large bowl.
Squeeze the cherry tomato juices into a small bowl before adding the tomato halves to the bread mixture.
Add the red onion, olive oil, and red wine vinegar to the bowl.
Tear up the basil leaves and toss into the salad mixture. Season with salt and pepper, to taste. Toss well.
Let the salad rest in the refrigerator for a few hours for all the flavors to come together.