Place flour, egg and bread crumbs in three separate bowls. Cut each mozzarella stick into thirds. Coat each piece in flour, then egg, then crumbs. Heat oil in a large frying pan over a medium flame. Fry cheese sticks on both sides until golden.

Mix dressing ingredients together. Combine tomatoes, onion, and fried mozzarella sticks and pour dressing over them. Toss and serve immediately.