Is there a jamf binary command to launch screen sharing to a particular machine or any way to do it via command line?
We need to start using screen sharing instead of ARD for security reasons and we'd like to tie it into webhelpdesk if possible which would require the able to launch a casper screen sharing session via terminal
I do not know of a way to do this via command line. There probably is one, but I am not aware of it. It sounds like you need to use Casper's screen sharing for security/logging purposes. The only way that I know of doing that is by using Casper Remote.
Now that I think about it, Casper Remote actually does the logging that you want done via a one-time policy scoped to specific machines, so I suspect that any command line way of doing this will most likely bypass the logging you're after as well. I suppose you might be able to script in a custom log back to the JSS, but I think that would be unnecessarily complex.
Casper Remote is just VNC over SSH, really no different from a security stand point from Remote Management / Screen Sharing which is can also be encrypted in OS X. If it's credentials, you can restrict which users have access to remote management / screen sharing. It's easier to run kickstart, but you can also run ssh -N -f -L 5901:localhost:5901 email@example.com
From there in terminal open vnc://localhost:5901
YMMV but the basic ideas hold true, create the ssh tunnel, have vnc traffic through port 590x run through it, bob's your uncle.