Preheat the grill. Bring a pot of salted water to a boil. Season the chicken breast with 1 tablespoon of sesame oil, salt and pepper. Place the chicken on the grill and cook for 4 to 5 minutes on each side. Remove from the grill and cool completely. In a saucepan, heat the remaining sesame oil. Add the garlic, ginger and chili paste. Cook for 1 minute, stirring constantly. Stir in the sugar and continue to cook for 1 minute. Stir in the hoisin, vinegar, peanut butter and water. Mix well. Bring the mixture to a simmer and remove from the heat. Cool the sauce completely. Add the noodles to the water and cook until tender, about 4 to 4 1/2 minutes, stirring the noodles constantly with chop sticks. Drain and rinse the noodles under cold water, using your fingers to separate the noodles while cooling. Toss the noodles in the peanut dressing. Slice the chicken, very thin, on the bias. Add the sliced chicken, peanuts and green onions to the pasta. Mix well. Season with salt and pepper. Serve the noodles cold.