Bring a large saucepan of water to the boil. Blanch the chicken for a few minutes, drain and discard the water.
Bring a large saucepan of water to the boil. Add the chicken, ginger and peppercorns. If necessary, add more water so that the chicken is covered. Cover and cook for 35-45 minutes over high heat or until the juices run clear. Remove from the saucepan and drain.
Horizontally cut the chicken into 2cm long pieces through the bone and skin then vertically cut into 2cm squares. Place the squares in a mixing bowl.
Combine the soy sauce, sugar, hot chilli oil and peppercorn oil in a bowl to form a sauce.
Pour the sauce over the chicken and toss well. Garnish with the spring onions and sesame seeds. Serve.
If your local supermarket doesn't stock Szechuen (also spelt Sichuan) peppercorns you can find them in Asian speciality shops or online.