Place ground chicken in a bowl and add a beaten egg, oyster sauce, soy sauce, fresh ginger, Chinese Five Spice and ground white pepper. Using my hands to incorporate.
Add Panko breadcrumbs, half a can of chopped water chestnuts, chopped cilantro and the zest of half a lemon. Mix to incorporate.
Roll or scoop into meatballs and brown on all sides in a skillet with some oil.
Lemon Sauce:
Place the juice from a large lemon, chicken stock, cornstarch, soy sauce, oyster sauce, sugar, vegetable oil, rice wine vinegar, sesame oil, fresh ground ginger and pinch of white pepper in a saucepan. Whisk together over medium heat until thickened.
Add the diced 1/2 lemon pieces (optional). Pour over the meatballs and cover with lid to steam 3 minutes. Garnish with chopped cilantro over meatballs. Serve with steamed rice.