At least 30 minutes before cooking, or even the day before, mix together the shaoxing wine or sherry, soy sauce, sugar and cornflour in a bowl. Trim and finely slice the pork, then add to the marinade and toss to coat. Cover and set aside (in the fridge if you’re marinating the meat for more than 30 minutes).
Peel and finely chop the garlic and ginger, trim and finely chop the chilli (deseed, if you prefer) and spring onions, then trim and chop the green vegetables into 4cm lengths. Rinse and drain the black beans.
Heat the oil in a wok until smoking hot. Drain the pork strips (reserve the marinade) and add to the wok. Stir-fry for 1 minute, then stir in the garlic, chilli and ginger and continue cooking for 1 more minute.
Throw in the greens, spring onions and black beans along with the reserved marinade, and continue to stir-fry over a very high heat for a few minutes, until the vegetables just begin to soften. Add a splash of water if it starts to stick.
Serve your stir-fry on a bed of steamed or sticky rice, with an extra splash of soy sauce, if you like.