I run Debian Wheezy and have Xfce as my X-Window Manager on virtual console 7, which starts up automatically.Once I've logged on and I'm using the xfce interface, is it possible for me to press Ctrl+Alt+F2 and move to another virtual console (non-X, console 2), and start an application in my, already running, x-session on console 7?Also, can I do this remotely: say I have a laptop running Linux with Xfce running at home. Can I start an application on that instance of Xfce over ssh from work? 
How to execute applications in existing X window from virtual console?
ssh;x11;xfce
Yes, you can. The program needs the $DISPLAY environment variable. In some more complex linux distributions you also need 2 other variables $XAUTHORITY and $DBUS_SESSION_BUS_ADDRESS.For example type in the terminal:DISPLAY=:0 xterm If it is still not working export the 2 varibales:export DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-LoSJ0EDrKV,guid=d46a103f4e55832818aa23c80000219cexport XAUTHORITY=/var/run/gdm/auth-for-user-6jbaaz/databaseTo find out the values of those variables, type echo VARIABLE in the graphic session.