Bring a large pot of salted water to a rolling boil. Add rigatoni and cook according to package instructions until al dente, about 10-12 minutes. Drain and rinse under cold water.

In a small mixing bowl, combine olive oil, lemon juice, honey, Dijon mustard, salt, and pepper. Whisk until emulsified and creamy.

In a large mixing bowl, combine cooled rigatoni, feta, cranberries, walnuts, spinach, and red onion. Toss until evenly distributed.

Drizzle vinaigrette over the salad mixture and gently toss to coat everything evenly without breaking the pasta or crumbling the feta too much.

Serve immediately or let it chill in the refrigerator for 15 minutes to enhance flavors. Garnish with additional walnuts or feta if desired.