Bring a large pot of salted water to a rolling boil over high heat. Add the rotini pasta and cook for 8 to 10 minutes until al dente. Drain and rinse under cold water.

While the pasta cooks, prepare the vegetables. Halve the cherry tomatoes, slice the cucumber, and thinly slice the red onion. Chop the fresh parsley.

If desired, whisk together olive oil, red wine vinegar, minced garlic, dried oregano, Dijon mustard, sugar, and salt and pepper until smooth.

In a large bowl, combine the cooled pasta with cherry tomatoes, cucumber, red onion, and Kalamata olives. Stir gently.

Pour two-thirds of the Italian dressing over the salad and toss until evenly coated.

Add the crumbled feta cheese and chopped parsley, gently stirring to combine and seasoning with salt and pepper.

Cover and refrigerate for at least 30 minutes to allow flavors to meld.

Before serving, stir and adjust seasoning or add more dressing if desired.