Is it possible to disable upper right corner action (menu avaliable by clicking it). I want to disable this menu at all.
And next - is it possible to disable menu avaliable by right mouse button clicking. I want to dosable user to make any changes in screen layout and adding icons, panels and so on. Can anybody help me?
I use KDE 4.6.1.

You likely want to look at the Kiosk framework. Instructions are available on KDE Techbase (http://techbase.kde.org) with regards to restricting the various actions available. This includes locking down Plasma.