Cook rigatoni in a large pot of salted boiling water according to package instructions until al dente, about 8–10 minutes. Drain and rinse under cold water.

In a mixing bowl, combine olive oil, lemon juice, honey, and Dijon mustard. Whisk until emulsified and smooth, then season with salt and pepper.

In a large salad bowl, combine cooled rigatoni, crumbled feta, cranberries, walnuts, spinach, and red onion. Toss gently to combine.

Drizzle the vinaigrette over the salad, and toss gently to coat evenly.

Serve immediately or chill for 15 minutes to enhance flavors before serving.