Dressing: Add all dressing ingredients to a jar. Secure the lid and shake well until combined.
Bring 12 cups of water to a rolling boil. Add 1 tablespoon salt, then pasta. Cook according to package directions until al dente. Drain, rinse under cold water for 20 seconds, and shake off any excess water. Transfer to a large bowl.
Shake dressing again and pour about ⅓ of it over the pasta. Toss to coat. Refrigerate the pasta until fully cooled.
Add spinach, chicken, red pepper, mandarin oranges, carrots, green onions, and cilantro to the cooled pasta. Gently toss everything together.
Add more dressing as needed (you might not need it all right away; the pasta absorbs it as it sits, so add gradually as needed). Top with toasted almonds, if using. Serve and enjoy!
