Begin by draining the canned tuna thoroughly, flaking it into a medium mixing bowl using a fork.

Chop the hard-boiled eggs into small pieces and add them to the bowl with the tuna, then add the finely minced red onion.

In a separate bowl, whisk together the non-fat plain Greek yogurt, Dijon mustard, and lemon juice until smooth and creamy.

Gently fold the creamy dressing into the tuna, egg, and onion mixture until well combined.

Season with sea salt and cracked black pepper to taste, then stir to ensure even distribution.

Cover and refrigerate for at least 15 minutes before serving to allow flavors to meld.