Preheat oven to 350°F (175°C).
Toss bread cubes with 2 tablespoons olive oil and spread on a baking sheet.
Toast in the oven for 10-15 minutes until golden and crisp. Let cool.
In a large bowl, combine tomatoes, cucumber, bell pepper, red onion, basil, and capers.
In a small bowl, whisk together dressing ingredients: olive oil, red wine vinegar, garlic, Dijon mustard, salt, and pepper.
Add toasted bread cubes to the vegetables.
Pour dressing over the salad and toss gently to combine.
Let the salad sit for 15-30 minutes before serving to allow the bread to absorb the flavors.