2 1/2 pounds mixed tomatoes, cut into bite-sized pieces
2 teaspoons kosher salt, plus more for seasoning
3/4 pound ciabatta or rustic sourdough bread, cut into 1 1/2-inch cubes (about 6 cups bread cubes)
10 tablespoons extra-virgin olive oil, divided
1 small shallot, minced (about 2 tablespoons)
2 medium cloves garlic, minced (about 2 teaspoons)
1/2 teaspoon dijon mustard
2 tablespoons white wine vinegar or red wine vinegar
Freshly ground black pepper
1/2 cup packed basil leaves, roughly chopped