Saute onions, garlic and chilli with oil in a large non-stick pan or skillet. Cook medium-high heat until onion sweats and fragrant, about 3-4 minutes.
Push onions to the rims of the pan, add pork mince and saute for about 2 minutes on high heat or until meat is brown but not cooked through. (note 3)
Mix shaoxing wine into the pan and allow the wine to evaporate. This will take about 1 minute.
Add carrots, beans, oyster sauce, say sauce, sugar, pepper. Mix and cook on low heat for 10 minutes, no lid.
Combine thickening mixture ingredients in a bowl, mix well and pour into the pan. Stir the pork and vegetables for 1-2 minutes on low heat.
To assemble the san choy bow, scoop 1 heaped tablespoon of filling into 1 baby gem lettuce leaf and (optional) top with finely sliced spring onion/scallions and fresh chilli. Repeat for remainder filling.