Tunneling of VNC over ssh in one command
Well actually two, but you stick them in one file that gets executed in bash:
ssh -fN -L 5900:localhost:5900 remotserver.example.com vncviewer -encoding tight -quality 5 localhost:0
The -N switch prevents commands to be sent to the remote host, the -f switch allows the terminal to come back and prompt for a vnc password that is triggered by the second line.
Warning: Haven't figured out how to exit cleanly. However the top rated answer here might do the trick:
Bash script to setup a temporary SSH tunnel - Stack Overflow