Tuskan Raiders are also known as Sandpeople. They live in small communities and don't live amongst the other races and people such as humans on their home planet of Tatooine. They survive by scavenging and attacking other races for supplies and food. They wear masks all the time so we don't see what they look like underneath. They travel using Banthas which are native to Tatooine.
A group of Tuskan Raiders killed Shmi Skywalker, mother to Anakin Skywalker and held her hostage. When Anakin went to rescue his mother, she died in his arms which angered the young Jedi. In revenge, Anakin slaughtered the entire Tuskan Raider camp including females and the children. He regretted his actions but over time he learned to forget what he had done.