Set a large a large frying pan over high heat with the two oil. Add the onions cook while stirring for two minutes, add the diced peppers, the garlic and ginger and cook for one more minutes . Add the rest of the ingredients except the corn starch and the soya sauce and bring to a boil
Dissolve the corn starch in the soya sauce add to the sauce while whisking boil for two minutes, remove from the heat and reserved.
Cook the tempura chicken in the fryer or in the oven until you achieved an internal temperature of 80°C (175°F).
Transfer the cooked chicken in a large bowl, add the sauce stir to coat the chicken.
Garnish with the toasted sesame seeds when serving.