For the vinaigrette, whisk vinegar, salt, pepper and honey. Add oil drop by drop to the vinaigrette. Peel and finely dice the onion and stir into the vinaigrette. Clean, wash and spin dry the salad and pluck into bite-sized pieces.
Wash and quarter the tomatoes. Roll up the roast beef. Arrange salad and roast beef on plates. Drizzle with salad dressing. Serve with tartar sauce.