Rinse the pork belly briefly in a cold running water. Place it in a pot and fill in water, just enough to cover the meat. Bring it to a boil and then slowly simmer for about 1 hour. Remove the pork belly from the pot and let it cool down and then put the meat into freezer for aout 15-20 minutes - this makes it easier to cut it thinly later on. Slice the meat to about 1/4-inch thickness and set aside
Chop the leeks at an angle into thin slices. Refer to how to wash the leeks properly
Heat 2 Tbsp oil in a wok over a medium flame, place the pork slices onto the wok and cook until they are brown on both sides, try not to crowd the wok as the meat will not brown properly because you ended up steaming the meat instead, so work in batches if you can and place the cooked meat on a clean plate while you working on others.
You should have some oil in the wok, add in the chili bean sauce, sweet chili sauce and black beans and stir-fry until fragrant. Add the leeks and wine and stir fry until they are soft. Add the pork slices back into the wok and stir to mix everything. Season with a dash of soy sauce and have a taste, it should be spicy, kinda sweet but not too much and salty. Adjust seasoning if you like. Then add the sesame oil, have a good last stir and transfer to a serving plate and serve immediately