Soak the rice sticks in tap water for about ten minutes or just long enough to soften a bit to separate them. You want them still underdone by the time you drain them and add to the pan so that they can soak up the nuoc mam pha.
Heat the cooking oil in a wok or frying pan. Saute the onion, garlic and ginger just until fragrant, about half a minute. Add the Chinese broccoli stalks. Stir fry for a minute. Add the Chinese broccoli leaves and carrot, season lightly with fish sauce, and cook for half a minute.
Add the drained rice sticks to the pan. Stir fry to coat the noodles with oil. Pour in about one-eighth cup of nuoc mam pha. Stir fry until the noodles have soaked up the sauce.
Taste the noodles, if it needs more seasoning, add more nuoc mam pha — sparingly because if you pour in too much liquid after the noodles have fully swelled, the excess liquid will make them soggy.
Add the pork cracklings to the noodles and toss just until heated through.
Sserve the stir fried rice sticks with oork cracklings and Chinese broccoli