Heat the oil in a frying pan over medium-high heat, and once it’s nice and hot, place the whole pork belly in the pan skin-side down. Once golden, turn it over and sear on the other sides too. The idea is just to get a lovely color, but you aren’t focusing on cooking the meat at all.
Put the seared pork belly, still whole, into a heavy-bottomed pan with a lid. Cover with water and add the spring onion, ginger, lemongrass, and red chili. Bring to the boil and then reduce to a simmer with the lid on for about 2 hours. During this time, skim off any fat that floats to the surface.
Remove the pork belly from the liquid and leave to cool enough for you to chop it up into roughly 2-inch chunks.
Mix together the oil, soy sauce, honey, brown sugar, ginger, and garlic.
Heat a frying pan over medium-high heat with a little oil, and then add your pork belly cubes. Fry for a few minutes until they have turned golden and the skin looks crispy.
Now pour the sticky sauce into the pan and cook for another 2 minutes, making sure to keep stirring as you don't want it to burn or caramelize. The pork should look gorgeously golden and sticky. Meanwhile, get your noodles on to boil, according to package instructions.
Add the julienned carrots to the noodles 1 minute before they finish cooking, and then toss the cooked noodles and carrots with a few spoons of the pork sauce to make them nice and saucy.
Serve with sliced cucumber. Sprinkle over some fresh chopped chili, some scallions, and sesame seeds.