Jawas were typically short rodent-like natives of Tatooine. They were passionate scavengers, seeking out technology for sale or trade in the deep deserts in their huge sandcrawler transports. A band of Jawas was responsible for locating C-3PO and R2-D2 and selling them to Luke Skywalker's uncle, Owen Lars. The Jawas also found Jabba the Hutt's rancor monster. They had a reputation for swindling, as they had a penchant for selling old equipment such as outdated faulty droids to moisture farmers. However, they are extremely passive beings, and hardly put up any resistance to colonists of their planet.
Take heed though--- if cornered, they may, indeed, take aim!
Jawas are commonly seen in pairs...
info and images: wikipedia, starwars
"Utinni!"
―A commonly used Jawa cry