Whisk together all the ingredients for the sauce except the water in a small bowl.
Heat the oil in a wok or large frying pan, add the ginger and cook for 1 minute. Stir in the chicken, spring onions and bean sprouts and stir-fry for 2 minutes. Add the noodles and stir-fry for 1 minute.
Pour in the sauce and measurement water and stir to coat the noodles and chicken. Heat until piping hot, then serve immediately garnished with coriander leaves.