Bring a large pot of salted water to a boil and cook the pasta according to the package instructions until al dente

In a large skillet, heat the vegetable oil over medium-high heat and cook the chicken until browned and cooked through, about 5-6 minutes

Remove the chicken from the skillet and set aside, then add the sliced onion and cook until softened, about 3-4 minutes

Add the minced garlic and grated ginger to the skillet and cook for an additional 1 minute, until fragrant

In a small bowl, whisk together the peanut butter, soy sauce, and coconut milk, then add the mixture to the skillet and stir to combine

Add the cooked chicken back into the skillet and stir to coat with the peanut sauce

Add the cooked pasta to the skillet and toss everything together to combine

Season with red pepper flakes and serve hot, garnished with chopped peanuts and fresh cilantro if desired