Open-Faced Tuna Melt Sandwich

Name: Open-Faced Tuna Melt Sandwich
Prep time: 5 min
Cook time: 5 min
Total time: 10 min
Cuisine: American
Ingredients: 1 4.5 ounce can tuna (in water) (drained); 1/4 cup carrots (minced); 1/4 cup minced celery; 1 tbsp red onion (minced); 1 tbsp light mayonnaise (Hellman's Light); 1 tsp red wine vinegar; salt and pepper; 2 slices whole wheat bread; 2 slices 2% reduced fat cheddar or American cheese; 2 slices tomato; oil spray (I used my Misto)