1. Bring a large pot of salted water to a boil. Cook the rotini according to package directions until al dente. Drain and rinse under cold water. Let cool completely.

2. In a small bowl or jar, whisk together olive oil, red wine vinegar, Dijon mustard, garlic, oregano, salt, black pepper, and red pepper flakes if using. Set aside.

3. Chop cherry tomatoes, cucumbers, red onion, and parsley. Pit and halve the olives if not already prepared.

4. In a large mixing bowl, combine the cooled pasta, vegetables, olives, and half of the crumbled feta.

5. Pour the dressing over the salad and gently toss to coat everything evenly.

6. Chill for at least 30 minutes to allow flavors to meld.

7. Before serving, give the salad a final toss, add remaining feta, and adjust seasoning if needed.