Prepare the dressing by combining all of the ingredients.
Cook pasta according to package directions. Rinse and drain pasta and add to a large bowl.
Toss the cooked noodles in half of the teriyaki sauce and refrigerate until cooled.
Season chicken breasts with salt and pepper and grill until cooked through. Use two forks to shred the chicken.
Combine the spinach, cooked chicken, peanuts, dried cranberries, sliced water chestnuts, mandarin oranges, and chopped onion in a large salad bowl.
Add the pasta to the bowl, along with desired amount of remaining dressing, and toss to combine.
