1. Combine first 9 ingredients in a large bowl; set aside.
2. Cook noodles in boiling water 1 minute. Add carrots and shrimp; cook 2 minutes or until shrimp are done. Drain in a colander over a bowl, reserving cooking liquid. Rinse noodle mixture under cold water; drain. Add noodle mixture, bell pepper, and 1/4 cup onions to peanut butter mixture, tossing to combine. Add enough of reserved cooking liquid to keep sauce creamy. Sprinkle with remaining 1/4 cup onions and peanuts.