Open the can of high-quality tuna packed in olive oil, drain gently, and flake into a medium mixing bowl using a fork.

Add halved kalamata olives, crumbled feta cheese, diced red onion, and chopped fresh parsley into the bowl with the tuna.

In a small bowl, whisk together freshly squeezed lemon juice and extra virgin olive oil until well combined; add dried oregano, salt, and black pepper.

Pour the vinaigrette over the tuna mixture and gently toss until everything is evenly coated.

Serve Mediterranean Tuna Salad chilled or at room temperature as desired.