Adding/removing moderators is done on Facebook, not CrushNinja. For your convenience, we have added a Manage Moderators button on the Moderators tab that takes you to the Page Roles area on Facebook.
Users must be assigned either the Admin or Editor page role on Facebook to be able to use CrushNinja with the page. If a user is not an Admin or Editor for a page, the page will not be visible in CrushNinja, and the user will be unable to view or publish submissions. Please see this Facebook help page for more information.