Here is the best way to wipe out every single bastard on that map. It is tough bcause there are infinite reinforcements.
Rebels - Spawn at the rebel camp as a rebel soldier. Get in a combat landspeeder and call a co-pilot in. Speed away to the tusken camp on the hill that overlooks the sarlaac. Wait for them to spawn and head down to do battle with your troops. Then get right into the cp. Get out and order your co-pilot to stop. He will give you cover fire and you can use it for cover. Blast any tuskens who spawn and fire at you. If they do not fire at you, let them run on. Once you get the cp to neutral, shoot any tuskens nearby and capture this cp. Get back in your speeder and head to the cp closest to the sarlaac pit. get out and hide in the rocks as you slowly convert this cp. Shoot any tuskens near it and also be on the lookout for the imperials. Once this is done, bring up the big map and look for any yellow arrows. Reach them and massacre the survivors. There are likely to be campers behind the large pillars of the tusken camp. Make shure every last one dies, because a single trooper could bring the entire army back. Once the last raider is killed, the species is wiped out and you can concentrate and fighting the empire. i almost always use this strategy.