Preheat your oven to 425°F (220°C). Line a large, rimmed baking sheet with parchment paper.

Cube the bread into 1-inch pieces, spread evenly on the baking sheet, drizzle with olive oil, sprinkle with salt, and toss until well coated. Bake for about 7 to 10 minutes until golden brown.

Whisk together the dressing by combining olive oil, red wine vinegar, dried oregano, minced garlic, salt, and ground black pepper in a medium bowl.

Chill the dressing by stirring in sliced onion and refrigerating while assembling the salad.

Assemble your salad by placing bite-sized tomatoes on a large serving platter, nestling half of the crispy croutons among them, and layering cucumber rounds and mozzarella over the salad.

Top the salad with the chilled onion mixture, drizzle remaining dressing, sprinkle with basil, olives or capers, and add extra black pepper and oregano if desired. Allow to marinate for 20 minutes to 1 hour.