You can set the form size--whether they're full screen or windowed--and the visibility of the nav pane, in Access Options, but you either do that or you don't. There's no additional "end user" mode. You can minimize the ribbon, but it's essential for some operations when there are visible records, which is almost always. Apart from that you can customize the ribbon, Google "Access Ribbon StartFromScratch USysRibbons" for more info on that, but it gets a bit advanced in a hurry.
Hope this helps,