Hi Gabriele.
In terms of disabling and creating writeback forms, listings and hierarchies this is something that can certainly be achieved through AdminConsole and there are details regarding this in the admin guide.
I don't think I've seen anything in the AdminConsole for amending the content or order of items in the menu panel (I couldn't see anything immediately obvious for this in the admin guide either when I just scanned through). I expect that it would be possible to do outside of AdminConsole by amending the XML in the configuration build.
An alternative approach that could be actioned solely from within AdminConsole would be examining where you could move modules between menus then renaming the menu name captions. Shuffle and rename rather than add and remove. It may(?) also be possible to omit any superfluous menus by disabling access to any entries beneath it using security permissions for roles with access to the system. I've not tried doing this but if you need to do everything from within AdminConsole (and assuming I haven't missed something obvious in how to do this) and not be digging into XML it would be worth a look.
Hope that helps.
Regards,
Stephen.