Tusken raiders are a hostile mob, native to the planet Tatooine. They don't spawn in the city of Mos eisley, they spawn in the desert.
The spawn rate for tusken raiders has been set to high, and your computer may experience lag.
Because tuskens are hostile they will attack anyone. A strategy for Jedi and Sith is to kill them from a distance using force abilities.
For bounty hunters, it's a lot easier because you have a ranged weapon at your disposal. Pick them off one by one with a high powered blaster. Tuskens occaisonaly spawn in a tribe in a village. The spawn rate for these places is not as bad as out in the desert, so you have a better chance of surviving.