Bring 6 quarts of water to a boil in a stock pot. Add the pasta and cook until al dente, approximately 7 minutes (taste to be sure). Reserve half a cup of the pasta cooking water. Drain the noodles, rinse under cold water, and drain again.

In a small saucepan, combine the peanut butter, soy sauce, vinegar, brown sugar, chili paste, cayenne powder, 1 tablespoon of sesame oil, and ginger. Bring to a simmer over low heat, stirring frequently with a whisk until the sauce is smooth, 2-3 minutes. Remove from heat and set aside.

Place the pasta in a large mixing bowl with the remaining 2 tablespoons of sesame oil. Toss well to coat the pasta. Refrigerate for 30 minutes.

While the pasta is cooling, toast the sesame seeds in a dry non-stick skillet until the seeds just begin to brown and give off a nutty aroma (shake the pan frequently to avoid burning the seeds). Remove the seeds from the pan and set aside.

When the pasta is cold toss in the cucumber, pepper, carrot, peas, cilantro and sesame seeds. Add the sauce to the noodles (If needed thin the sauce with the reserved pasta water). Toss well to combine. Garnish with scallions.