Place the chicken in a shallow dish. Combine the soy sauce, mirin and sugar, add to the chicken and toss well to coat. Set aside to marinate for 15 minutes.
Meanwhile, cook the noodles according to the packet instructions, then drain, refresh in iced water, drain again and chill.
Thread the chicken cubes on to metal skewers and barbecue or grill for 2–3 minutes on each side.
Toss the noodles with a little sesame oil and serve with the chicken and extra sesame oil and soy sauce.