1 1/2 tablespoons red wine vinegar
1 tablespoon balsamic vinegar
1/4 teaspoon salt
1/8 teaspoon fresh-ground black pepper
1 teaspoon dried oregano
1 teaspoon dried basil
1 1/2 tablespoons olive oil
3 vine-ripened tomatoes, each cut into 6 slices
1/3 red onion, thinly sliced
6 (4 ounce) mild Italian sausage links
6 French rolls, halved lengthwise
Preheat an outdoor grill for medium heat.
Whisk together red wine vinegar, balsamic vinegar, salt, pepper, oregano, basil, and olive oil in a small bowl. Arrange the tomato and onion slices on a serving platter, and pour dressing overtop. Allow to marinate at room temperature while you cook the sausages.
Pierce the sausages with the tip of a sharp knife a few times, then place onto the grill. Cook until no longer pink in the center, turning them frequently so that they cook evenly and have lightly browned, about 15 minutes total. Serve on French rolls with marinated tomatoes and onions.