Tuna Melt Pita Sandwiches

Ingredients

• 1/4 teaspoon salt
• 1/4 teaspoon ground black pepper
• 1/4 teaspoon garlic powder
• 3 tablespoons mayonnaise
• 1/2 cup cheddar cheese, shredded
• 1 celery stalk, diced
• 1 (5 ounce) can of tuna, drained
• 1 large dill pickle, diced
• 2 tablespoons red onion, diced
• 2 Greek style pitas
• sliced tomato (optional)