Lychees and longans are considered exotic fruits in some parts of the world and are sometimes available only in cans. But they can usually be found where there are large Chinese communities. In Hong Kong the fruits are inexpensive and available fresh. Longans imported from Thailand and other Southeast Asian countries mean this fruit is available almost year-round, but the brief season for lychees means the fruit is usually sold from June to August only.
When buying the fresh fruit, look for pliant skins covering firm flesh. If the skin is brittle and brown the fruit is old. Longans are smaller than lychees and the skin is smooth and yellowish-brown. The skin of lychees is bumpy and the colour is usually a shade of red. The best lychees have small seeds and are called lo mai chee; fruit vendors will usually cut them in half to display the seed.
Both fruits, which belong to the same family as durian and rambutan, are considered yeet hay, or 'heating', and if you eat too many they can cause insomnia, nosebleeds and a dry cough.
There are few preparations for the fresh fruit because it is hard to improve on something so delicious on its own. They do, however, make an excellent sorbet if you are fortunate enough to have an ice-cream maker.
Peel the fruit and remove the seeds, then weigh the fruit and puree it. Make a sugar syrup with two parts sugar mixed with three parts boiling water and let it cool. Mix the puree with an equal weight of the sugar syrup, adding fresh lemon juice to taste (it should be fairly tart) then process in an ice-cream maker.
Lychees and longan are also available canned or dried. The canned fruit is fine in lychee cocktails. Shake vodka with ice and a little syrup from the canned fruit, strain into a chilled Martini glass and add a canned lychee. This drink can also be made with sake.