Begin by bringing a large pot of salted water to a rolling boil. Add the rotini pasta and cook until al dente, about 8-10 minutes. Drain and rinse under cold water. Set aside to cool.

While the pasta cools, chop the cucumber, red onion, and green peppers into bite-sized pieces, and place them in a large bowl.

Add the chopped vegetables, parsley, and feta cheese to the mixing bowl. Toss gently to combine.

In a separate bowl, whisk together lemon juice, olive oil, white vinegar, onion powder, garlic powder, salt, and pepper to make the dressing.

Pour the dressing over the vegetable mixture and gently mix until everything is well-coated.

Fold in the cooled rotini pasta gently until evenly mixed.

Cover and refrigerate for at least 2 hours to allow flavors to meld.