Arrange the onions on a tray and place the pork on top. Combine the star anise, ginger, garlic, soy, oyster, rice wine, sugar and sesame oil in a bowl with the five spice. Pour over the pork and rub in.
Meanwhile, shred the spring onions and put into a bowl of iced water to crisp and curl up. Toss the carrot and celery with the vinegar, pinch of sugar and remaining 1tbsp of sesame oil.
Serve the lettuce leaves piled with the sticky pork belly, the crispy spring onions and pickled vegetables, wrap up and devour.