Cook the pasta according to package instructions, then drain and rinse.
Season the chicken breasts, grill them until fully cooked, then slice.
In a large bowl, combine the cooked pasta, sliced chicken, cherry tomatoes, cucumber, red onion, olives, and feta cheese.
In a separate bowl, whisk together olive oil, red wine vinegar, oregano, salt, and pepper.
Pour the dressing over the salad and toss gently to coat.
Let the salad sit for at least 15 minutes before serving.
Taste and adjust seasoning if necessary, then serve chilled or at room temperature.