Boil a large pot of salted water and cook rotini according to package instructions until al dente.
Drain the pasta and rinse under cold water to stop the cooking process and remove excess starch.
In a large mixing bowl, whisk together olive oil, red wine vinegar, oregano, garlic powder, salt, and black pepper to create the dressing.
Add the cooled pasta, cherry tomatoes, cucumber, red bell pepper, olives, red onion, and parsley to the bowl.
Toss all ingredients thoroughly until evenly coated with the dressing.
Cover and refrigerate for at least 30 minutes before serving to allow flavors to meld.