You can use sudo/gksudo to run any application as another user.
To switch to user uname:
Code:
sudo -u uname -i
<run commands as uname>
exit #or press Ctrl+d
For GUI applications use gksudo:
Code:
xhost +SI:localuser:uname
gksudo -u uname -l "firefox"
gksudo -u uname -l "nautilus --no-desktop"
xhost -SI:localuser:uname
Or you can start a gnome-session on one of the virtual terminals:
Code:
sudo -u uname -i xinit /usr/bin/gnome-session -- :3 vt9
The above code starts the session on vt9, so you can press Ctrl+Alt+F7 (or F8) and Ctrl+Alt+F9 to switch back and forth between the sessions.