Combine shredded chicken, celery and buffalo wing sauce in bowl; set aside.
Cut 16 (1/2-inch) slices from French bread. (Use remaining bread as you wish.) Butter 1 side of each bread slice. Spread about 1 teaspoon salad dressing onto other side of each bread slice. Place 1 piece cheese over dressing on 8 bread slices; top with 1/3 cup chicken mixture, 1 piece cheese and remaining bread slices, buttered-side up.
Place sandwiches onto grill. Grill, turning once, 4-5 minutes or until bread is toasted and cheese is melted.