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 olive oil, lemon juice, dijon mustard, salt, black pepper, and parsley.

Pour the dressing over the pasta salad and toss to combine. Adjust seasoning if necessary. Serve chilled or at room temperature.