Add tuna, mayonnaise, celery, red onion, capers, lemon juice garlic, parsley and dijon mustard to a mixing bowl.
Toss ingredients together, while seasoning with salt and pepper to taste.
Notes
*To drain tuna I cut the can lid with the can opener then turn upside down and press down on the tuna with the lid to remove excess liquid. Chunk light tuna would work as well but be sure to drain very well, pressing out excess liquid and start with 3 Tbsp mayonnaise.
To make it healthier substitute 1/4 cup Greek yogurt and 1 Tbsp mayonnaise.
Try serving over bread slices, pita bread, croissants, bagel things, tortillas, or lettuce leaves.