Bring a large pot of salted water to a boil. Add rigatoni and cook until al dente, about 8-10 minutes. Drain and set aside.

Rinse the drained rigatoni under cold water to cool it down. Let it drain thoroughly.

In a large bowl, combine the cooled rigatoni, spinach, cherry tomatoes, feta, cranberries, and red onion. Toss gently to mix.

In a medium bowl, whisk together olive oil, lemon juice, Dijon mustard, garlic powder, salt, and pepper until smooth.

Pour the dressing over the pasta and vegetable mixture. Toss gently to coat all ingredients.

Cover the salad and chill in the refrigerator for at least 30 minutes before serving.