I mark this as solved
x11vnc is the debian package name you look for. This app also can disable the screensaver and keyboad repeat while connected.
after having started it manaully for the first time (in order to set the password interactively), you can
remote connect to the X session using:
ssh -f remote-box -L 5913:localhost:5900 x11vnc -usepw -display :0 -nodpmi ; xvncviewer localhost:13