Subway Classic Tuna (Copycat Recipe)  You will need: 24 ounces chunk light tuna in water, drained   1/3 cup mayonnaise  2 teaspoons lemon juice  1/4 teaspoon salt    1. Combine all ingredients in a small bowl. Stir vigorously to break chunks of tuna. Chill until cold.   2. Use an ice cream scoop to serve two scoops of tuna on each 6-inch sub roll.  Makes enough tuna for three 6-inch sandwiches.