Bring a large pot of heavily salted water to a boil. Add a splash of oil to the water then cook the spaghetti according to the pasta directions. Drain.
Put the garlic and ginger in a blender or food processor and pulse several times to mince. Add the ½ cup oil, peanut butter or sunflower seed butter, soy sauce, vinegar, mirin, honey, sesame oil, and red pepper flakes and blend until smooth.
Pour about three quarters of the sauce onto the hot spaghetti, add the chicken and toss to coat. Let sit for a few minutes so the noodles and chicken absorb flavor from the sauce. Add the peppers, scallions, cilantro and more sauce, toss well, sprinkle with sesame seeds and serve with any remaining sauce on the side.
(adapted from CAROL KICINSKI from simplyglutenfreemag)