From that link, I can now set chromium-browser in ubuntu - gnome in kiosk mode (fullscreen mode) to display a web page (acting as screensaver). Everything is working fine. But I want to setup it more security by adding a lock screen to ask user+password to unlock to user's desktop. gnome-screensaver or xscreensaver -lock can't be used here because if I run gnome-screensaver, xscreensaver lock screen, it will be in foreground of the screen, we can't see chromium-browser anymore. If we supply wrong password there, the gnome-screensaver is still in foreground.
I have checked xlock, it could be fit my need, but it doesn't support PAM in my environment.
I want to ask if there is a lock screen program to display a dialog box to ask user, password with PAM support, not running in fullscreen.
Another thing I want to ask is there any terminal command can blank, turn off the secondary monitor.
A thread which I asked in ubuntuforums: http://ubuntuforums.org/showthread.php?t=2096471