If you visit any decent-sized Chinese market you'll find an impressive array of Chinese sausage, known commonly by its Cantonese name lap cheong. The term, in fact, is generic and covers a broad range of sausage, both fresh and smoked, and extends to sausages from Vietnam and Thailand. Some kinds will be made with liver, some will be dry to the point of rock-hardness, some will use soy sauce and others, a more straightforward mixture of sugar and fatty pork.
What unifies all kinds of Chinese sausage is an extremely sweet flavor and an emulsified texture that makes even the fresher links taste like meat candy.
When shopping for Chinese sausage it's helpful to keep in mind what dish you want to make. While the links will vary in degrees of sweetness and dryness, the smoked, shriveled kind of Chinese sausage tends to be too dry to use in lieu of regular sausage. The driest of the bunch is so firm that soaking the links in water, as you would do for hard Chinese bacon, is the best way to bring out the flavors and textures of the sausage.
Due to the meat's dryness and intensity in flavor, the sausage is often used as a flavor component in other dishes. Links are diced and rendered, until only a hint of the actual sausage is left. Chinese sausage shows up in turnip cake, for instance, and if you frequent the dim sum carts, you'll notice it in a variety of other snacks like the various deep-fried taro root concoctions.
If you'd prefer something that tastes closer to what we think of as a juicy sausage stuffed in a crispy casing, then look for the fresh variety of Chinese sausage. Significantly less shriveled and softer, the links will feel greasy and contain discernible chunks of pearly-white fat. Because of the higher-than-average fat and sugar content, this kind of Chinese sausage browns quickly and renders a lot of lard, making it an ideal component in stir-fries.
While slices of Chinese sausage are good in any stir-fry, my favorite way to use them is in a rice or noodle dish, so the staple soaks ups the fat rendered from the sausage. Used in fried rice, the sausages impart a rich taste to each kernel.
The only trick to using fresh lap cheong is to carefully monitor the browning process, as the sugar content in the meat makes the slices of sausage easy to scorch. Otherwise, just keep your fried rice simple: when the sausage is this unbelievably fatty and sweet, adding too many ingredients to the wok would just be overkill.