Cook the pasta according to package directions. Drain and run under cold water to stop it cooking, stirring occasionally. Set aide once the pasta's cool to the touch.
Let a medium sized skillet heat up over medium heat. Add the sesame seeds, and cook stirring occasionally for 1-2 minutes, or until lightly toasted. Set aside.
Add the oil, soy sauce, vinegar, sesame oil, sugar, sesame seeds, salt & pepper to a large mixing bowl, and whisk together until the vinaigrette is evenly incorporated and smooth.
Add the pasta to the mixing bowl, and toss together until the pasta's evenly coated.
Stir in the chicken, cilantro, spinach, carrots, and peppers, if using. Toss and serve.