Use 2 tablespoons of the cooking oil from the pork and heat in a clean wok over a medium-high heat. Fry the garlic and chilli for about 20 seconds until fragrant, don't let it burn! Chuck in the kale and stir fry for a few seconds then add the the oyster sauce, the soy sauce, the pepper, the sugar and a few splashes of water. Turn the heat up and keep it all moving for a minute or so. Chuck in the crispy pork and stir fry for another 30 seconds.