Sprinkle corn flour, salt and pepper on chicken pieces and toss well.
Heat 20 ml oil in a large wok or non-stick saucepan and pan-grill chicken (in batches if required) on high heat. Turn the chicken over after a minute and grill both sides. Remove the chicken with a slotted spoon and set aside.
Add the remaining oil, add red chillies and saute until darkened. Add green chillies and ginger; stir-fry for 2-3 minutes. Add onions and toss well for 1 minute. Add green peppers, dark and light soy and mix well. Add stock and bring mixture to a boil.
Dissolve the corn flour in 1 ½ tbsp of cold water; mix well.
Once the stock begins to boil, add the corn flour paste stirring vigorously to avoid any lumps. Add the grilled chicken, spring onions, and cook for a further 2 minutes on high heat. Check seasoning, drizzle sesame oil and serve hot with vegetable or egg fried rice.