Bring a large pot of salted water to a boil. Add the rotini pasta and cook according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large mixing bowl, combine the cooled pasta, cherry tomatoes, cucumber, bell pepper, red onion, black olives, and feta cheese.

In a separate bowl, whisk together the olive oil, red wine vinegar, Dijon mustard, garlic powder, oregano, salt, and black pepper until well combined.

Pour the dressing over the pasta salad and toss gently to combine. Adjust seasoning if necessary. Serve immediately or refrigerate for up to 2 hours before serving.