You can set all options on a per-host basis (wild-cards allowed) in either $HOME/.ssh/config for user specific settings or in
/etc/ssh_config for all users on the machine.
To tunnel your vnc session when connecting to <somehost> you'd want to add something like this:
Host <somehost> #this should be a valid host name or ip address
will give you a list of the many other options you can configure.