Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente, about 8-10 minutes. Drain and rinse under cold water to stop the cooking process, then set aside.

In a small bowl, whisk together fresh orange juice, olive oil, honey, Dijon mustard, salt, and black pepper. Mix until well combined and creamy.

In a large mixing bowl, combine the cooked penne, crumbled feta cheese, dried cranberries, toasted walnuts, baby spinach, and thinly sliced red onion. Toss gently.

Drizzle the prepared orange vinaigrette over the salad. Toss everything gently yet thoroughly to coat each component.