Open both cans of tuna and pour the contents into a fine-mesh strainer set over a bowl. Press the tuna gently with the back of a fork to release excess liquid.

Flake the drained tuna with a fork into a large mixing bowl, breaking up any large chunks.

Add mayonnaise, fresh lemon juice, and Dijon mustard to the tuna in the bowl. Stir until fully combined and the mixture is uniformly creamy.

Sprinkle salt and freshly cracked black pepper over the mixture to taste.

Dice celery, red onion, and bell pepper into small, uniform pieces.

Gently fold the diced celery, red onion, bell pepper, fresh parsley, and capers into the tuna mixture using a fork or wooden spoon. Avoid overmixing.

Taste a small spoonful plain, then on a cracker if possible. Adjust by adding more lemon juice, mayo, salt, or pepper as desired.

Spoon the tuna salad onto your choice of base: toasted bread, crackers, lettuce wraps, or fresh greens. Serve immediately.