Heat oven to 200F.
Scrub the skin of the pork belly with a handful of salt or sugar. Rinse and pat dry.
In a pot, stir together the dark soy sauce, wine, water star anise, ginger and honey. Add in the pork belly. Create a snug tent with the tin foil - use your hands to mold the tin foil over the pork belly and liquid. Cover pot with lid.NOTE: If you are cooking sous vide, omit the water, and just add all ingredients to sous vide bag. Sous vide 176F/80C for 6-8 hours. Roast at 200F for 4-6 hours. When done, lift out pork belly and dice. From the sauce, discard the ginger and star anise. Simmer the sauce for a few minutes, until reduced and thickened.
To make the slaw, combine bell peppers, carrots and cucumber with the seasoned vinegar. Taste, and adjust with more vinegar if needed. Slaw should be slightly sweet and tangy.
Heat a wok or saute pan over high heat. When hot, swirl in the cooking oil. Add the pork belly dice in a single layer and let cook for 1 minute, stir and repeat for all sides of the pork belly. Add in the reduced sauce and stir well, let sauce reduce even more (about 1 minute). Serve with lettuce cups and top with a sprig of cilantro.