Sichuan (Szchesuan) pepper is also known as Chinese coriander.
It is widely used in Chinese and Indian cuisine. It is not really pepper or chilli, Sichuan pepper belongs to the same family as citrus. The taste and smell is quite unique and different from other peppers (black, white pepper, chilli). It goes well with meat marinades or fried vegetables.

Sichuan's taste is sharp, rather mild and sour, lemony, with a slightly numbing, astringent, layered sensation (something similar to drinking carbonated drinks). 
Dry roast before consumption.