It is impossible to know for sure what the rioters wanted. It is very likely that there were many different motivations because there were so many different rioters. Here are the two major schools of thought as to what the rioters wanted or hoped to achieve.
One school of thought says that the riots were a way of lashing out against an oppressive and uncaring society. This school of thought argues that the rioters were expressing their frustration with a society that keeps them down and does not help them to have better chances in life.
A second school of thought is much more critical of the rioters. It argues that they were motivated mainly by greed and a desire to do mindless violence. In this view, the rioters were criminals, or at best people with shaky moral values who got swept up in a mob mentality. They were using the police killing and the protests simply as a cover for their desire to either commit violent acts or to get valuable goods without paying.
It is probable that some rioters fell into each of these categories and some fell into others or into both. There is no way to know for sure.
Thank you pohnpei397.