Bring a large pot of water to a boil; add chicken and cook for 2 to 3 minutes. Drain and discard water.
Bring a large pot of fresh water to a boil; add chicken, ginger, and peppercorns. Add more water if needed to cover chicken completely. Cover and cook over high heat until chicken is no longer pink and juices run clear, 35 to 45 minutes. Drain and discard water.
Horizontally chop chicken into 3/4-inch pieces, cutting through the bone and skin. Vertically chop into 3/4-inch squares; transfer to a bowl.
Combine soy sauce, chile oil, sugar, MSG, and Sichuan peppercorn oil in a bowl to form a sauce; pour over chicken and toss well. Garnish with spring onions and sesame seeds.