Preheat the oven to 325°F. Cut the baguette lengthwise and drizzle all sides with olive oil. Then rub the baguette on all sides with the garlic.
Cut the baguette into 1-inch cubes and place them into a 9 × 13-inch baking dish. Add the salt and pepper and toss. Bake for 20 minutes until lightly golden then remove from the oven to let cool.
Slice the heirloom and cherry tomatoes into bite-sized pieces. In 4 shallow bowls, combine ½ cup of tomato water with the tomatoes, arugula, and basil leaves. Drizzle with olive oil and add a few croutons just before serving.