Cook the pasta according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large mixing bowl, combine the cooked pasta, drained tuna, cherry tomatoes, cucumber, red onion, and bell pepper.

In a small bowl, whisk together mayonnaise, olive oil, lemon juice, oregano, salt, and black pepper.

Pour the dressing over the pasta mixture and toss until everything is well coated.

Garnish with fresh parsley and serve chilled or at room temperature.