Place a wok or large frying pan over medium heat and add the vegetable oil. When the oil is hot, add the garlic and chiles and stir-fry until fragrant, 3 to 4 minutes. Add the pork belly and stir-fry until the fat is translucent, about 3 minutes.
Tilt the wok to pour off all but 1 to 2 tablespoons of the fat. Add the leeks and stir-fry until tender, about 3 minutes.
Add the sugar and stir-fry for 1 minute more. Stir in the soy sauce and serve immediately.
Reprinted with permission from Root-to-Stalk Cooking: The Art of Using the Whole Vegetable, by Tara Duggan, copyright 2013. Published by Ten Speed Press, a division of Random House, Inc.
Harold McGee, the author of Keys to Good Cooking, is an expert on the chemistry behind food and cooking. McGee recently made his first trip to China, where he learned more about rice wine.