Make tapioca flour slurry. Mix together tapioca flour with 50ml water until well-combined. Set aside.
Whisk together light soy sauce, thick soy sauce, black sesame oil, brown sugar, shaoxing wine, pepper and 1 tbsp of cooking oil until well-combined. Leave aside.
Crush garlic and mince roughly. Slice the ginger into long, thin strips. Cut spring onions's stems and leaves into 1 inch length pieces, chopping the last 1/3 of the leaves into smaller pieces for garnishing.
Cut the chicken wings into half, drummettes and wings.
Sprinkle salt over the chicken, and rub to marinate evenly. Repeat with the mixed sauce. Cover with cling wrap and leave in the fridge for 1-2 hours.
Add 2 tbsp of cooking oil in a pan over medium heat. Add the garlic, ginger and stems of the spring onions. Stir fry until soft, translucent and fragrant.
Add the chicken wings. Stir to coat the chicken with the oil. Cover the pan and switch the heat to low. Let it braise for 20 minutes. Stir occasionally to prevent the bottom layer from burning.
After 20 minutes, the chicken should be cooked. Check the tenderness of the meat. If it's still tough, add 250ml of water, raise the heat to medium, cover the pan and continue braising for another 20 minutes.
Once the chicken is softened, taste and adjust as preferred.
Add the flour slurry and the 1 inch-length spring onions. Give it a quick stir and switch off the heat.
Dish out on a serving plate and garnish with cut spring onions. Serve with rice.