Place a pan over medium-high heat and allow it to come up to temperature. Add your 1tbsp of oil, heat it up for a minute, then add your chicken and spread it out. Cook for five minutes, only stirring once or twice, allowing the pieces to brown. Pour the sauce in, followed by 50ml of water and reduce until thick and glossy. Stir most of the spring onions and sesame through the chicken, leaving some for garnish.