English Muffin Tuna Melt

Name: English Muffin Tuna Melt
Ingredients: 2 English muffins split and toasted and lightly buttered; 1 5 ounce can tuna, drained I used white albacore; 1 tbsp finely chopped onion; 2 tbsp finely chopped celery; 2 tbsp mayonnaise, more if you like it really creamy; 1 tsp fresh lemon juice; 1/4 tsp garlic powder; 1/4 tsp black pepper; 1/4 tsp dijon mustard; 4 slice of fresh tomato; 4 slice sharp cheddar cheese-or cheese you like; 4 slice pepper jack cheese- or cheese you like; 1/2 cup shredded lettece for garnish