Well the sensible thing to do would be to let the Sand People Elite attack you and snatch their clothing - as far as I can tell the ONLY way to get past those turrets alive, unless you're pretty damn strong.
Also, you will need to take HK-47 with you, because he is the only one who can interact with the sand people. Which makes for some quite funny dialogue

. That is, unless you simply want to murder all of the sand people and their chieftain.