If you have a need to disconnect a user from the firewall forcibly. There are a few ways I am aware of that will force users off the VPN.
Installing Security Policy (link)- clears the cached authentication of the remote user, although this doesn’t seem to disconnect them it prompts them to re-enter credentials.
Expire the user with SmartDashboard or change the user’s password and then push the Security Policy.
My favorite method is to SmartVire Monitor:
Open SmartView Monitor > Users > click on any of the options: Users by Gateway, Users by Name, All Users, CheckPoint Mobile Users and after finding the user you want to disconnect, right click on it and Reset Tunnel.