Put the chicken in a bowl. Add the soy sauce, sugar and sesame oil and stir well. Cover and leave to marinate at cool room temperature for 15 minutes.
Strain the chicken and reserve the marinade. Add the oyster sauce and rice wine vinegar to the marinade and set aside.
Heat half the vegetable oil in a wok or large frying pan until starting to smoke. Add the chicken and stir-fry over a high heat for 2–3 minutes until lightly golden. Remove from the pan with a slotted spoon.
Heat the remaining oil in the pan, add the spring onions, garlic and ginger and stir-fry over a high heat for 1 minute. Return the chicken to the pan with the noodles and marinade mixture and toss for 2 minutes until heated through.
Stir through the bean sprouts and serve in bowls, garnished with red chilli slices.