The only way to remotely restart Ksenos is through the web UI, and for this the web server must be enabled (and possibly port forwarded).
To remotely restart Ksenos:
- Enable the web server from Ksenos settings – by default it binds to port 80.
- Connect to the server IP via browser, login and click Restart Ksenos from the top right corner.
If there is no static IP or if the system is behind a NAT, you will have to port forward the connection. Port forwarding is different for each router, but portforward.com has a lot of guides for different hardware. Also see Remote access from an external network or the Internet.