Suàn Ní Huángguā (蒜泥黄瓜 - Chinese cold garlic cucumber)
While Chinese cuisine is familiar to most people in the West, in general, the variety of Chinese foods found in most restaurants in the Americas is limited to a very narrow range of dishes. One thing that is painfully absent from most Chinese menus in the West is the concept of the 冷菜 (lěng cài - cold dish). This category encompasses a broad range of Chinese dishes, all of which are served cold (at room temperature) rather than warm or hot.
One of the easiest and most common of these dishes is cold garlic cucumber. The fact is that this dish is eaten all over China, showing very little prejudice from region to region. It is found everywhere from dim sum houses to Chinese "fast food" buffets to hole-in-the-wall four-table storefronts to the finest sit-down dining rooms. As such, it, along with 凤爪 (fèng zhǔa - chicken feet), 花生米 (huā shēng mǐ - fried peanuts), and 泡菜 (pào cài - pickled vegetables) is a stable mainstay of the cold dish pantheon.
The fatter cucumbers most commonly found in North America and the long, thin, bumpy cucumbers more common in China are both the same species (cucumis sativus), however, I find that the size of the Chinese-style cucumber is superior for two reasons. Firstly, the bumpy skin holds the crushed garlic on the surface of the cucumber slices and secondly, the thinness of the Chinese cucumber makes it easier to cut it into pieces that each have some of the vegetable skin exposed. With the fatter, smooth cucumbers, you'll doubtless end up with some pieces with no skin at all. I've also noticed that the bumpy variety of cucumber is less often covered with an inch of paraffin, which the smooth ones you'll find at the Safeway often are.
Wash the cucumber and slice into generously thick, long pieces (approximately .75cm x .75cm x 7cm). Stack the pieces in three or more layers on the serving dish. Place oils, salt, soy sauce, and suan ni into a small bowl or cream pitcher and mix them evenly. Drizzle the solution over the cucumbers.
In some regions, the cucmbers are beaten with the blade of a 菜刀 (cài dāo - Chinese cleaver) to bruise them slightly. One might also put the cucumbers into a plastic storage container (with a lid), pour the sauce into the container, put the lid on and shake the container vigorously, which will both bruise the cucumber and distribute the sauce on the surface of the cucumber.
While this is technically a cold dish, chilling the cucumber before or after preparation is not recommended. The dish is better served at room temperature.