Cook the rotini pasta according to package instructions; drain and rinse under cold water.
In a large bowl, combine the cooked pasta, cherry tomatoes, cucumber, red and yellow bell peppers, and red onion.
Add the sliced Kalamata olives and crumbled feta cheese to the bowl.
In a separate small bowl, whisk together the olive oil, red wine vinegar, dried oregano, salt, and pepper.
Pour the dressing over the pasta salad and toss gently to combine.
Taste and adjust seasoning if necessary.
Chill in the refrigerator for at least 30 minutes before serving.
Serve cold or at room temperature.
Garnish with additional feta and olives before serving, if desired.
Enjoy this dish as a side or a light main course!