Spread 1/2 teaspoon mustard on top half of each roll; set aside. Place bottom halves of rolls on a baking sheet. Top each with 2 cheese slices, 1/4 cup sliced artichoke, and 2 tomato slices; drizzle each with 1 1/2 teaspoons dressing. Broil 2 minutes or until cheese melts. Cover with tops of rolls.