YOU MUST BE AN INTERNAL USER WITH ADMIN PERMISSION TO ACCESS THIS FEATURE!
Login to back end FastGem (ADMIN).
In the horizontal tool bar across the top of the screen, click on 'Menus' & then, click on 'All Menu Items'.
Click the checkbox selection to the left of the menu item you want to REMOVE from the front end's visibility. (We will use 'Leads' as an example.)
Click on 'Unpublish'. All done.
Now, the 'Leads' menu item will no longer be visible from Front-end FastGem.