Cook the noodles according to package directions.
While the noodles cook, make the spicy peanut sauce. Place the peanut butter in a small bowl and pour in 3 to 4 tbsps. of boiling water. Mix to form a smooth paste. Add the rest of the ingredients and stir to blend.
Heat the cooking oil. Add the chicken and stir fry just until the meat changes color. Pour in a splash of fish sauce. Season with pepper. Continue cooking until the liquid has been absorbed by the meat and the meat pieces start to brown along the edges.
Add the garlic and onion. Stir fry for half a minute.
Add the green beans and carrot. Season with more fish sauce and pepper. Stir fry for one to two minutes.
Toss together the noodles and the spicy peanut sauce.
Divide the noodles among individual plates.
Top the noodles with the stir fried chicken and vegetables.
Garnish with sesame seeds, crisp onion slices and toasted garlic bits.