Toast sesame seeds until fragrant and grind to a powder.
Marinate chicken with egg, sesame powder, garlic paste, starch, chilli oil, pepper and salt. Rest 15–20 minutes.
Air fry at 200°C for 13–15 minutes, shaking halfway, until crisp.
Mix sauce: sesame powder, soy sauce, vinegar, chilli crisp, sugar, salt and hot water/stock.
Stir fry: heat oil, sauté garlic paste and chillies. Add onion and capsicum; cook on high 1–2 minutes.
Add sauce + ⅓ cup water, simmer until glossy. Toss in the chicken.
Finish with spring onion greens.
