Run a VNC Server on the computer you wish to have remote access to, and open up ports 5900 and 5901 on any firewalls/routers you have managing your network. Forward the open ports to only the machine you wish to access, (such as 192.168.1.2) You will now be able to connect to your Linux environment by entering in the external IP address of the network, and port number, (example:
http://user: pass@192.0.0.1:5901) Substitute user for the actual username, and pass for the actual password. Remove the space between the colon after user and before pass. Replace 192.0.0.1 with the actual public IP to the network you wish to connect to.