This is the article for UberMenu 2, if you are using UberMenu 3, please see the UberMenu 3 RTL Guide
UberMenu 2 does not currently have an option to enable RTL, but in general customers just need to add this CSS snippet:
#megaMenu ul.megaMenu li.menu-item, #megaMenu ul.megaMenu li.menu-item.ss-nav-menu-mega ul.sub-menu-1 > li.menu-item{ float:right; text-align:right; }
For details on implementing a complete RTL stylesheet, please see the Codex: Right-to-Left Language support