Cygwin's SSHD is not securee, as the docs will tell you. Essentially, there's a shared memory space via the CYGWIN32.DLL, which is accessible to all processes on the system. So while useful for lightweight applications, I wouldn't use it as a publicly-facing service.

What you want to do is set up a box with a decent SSHD, and forward one of its ports to the appropriate port on your ultimate destination box. Read up on port forwarding for how to do this, it's pretty straightforward.

Once done, you'd connect to the forwarded port of the SSHD server, which in turn will forward you to the appropriate port on the destination box. You can set these ports to be symmetric (identical) or assymetric (eg: port 5213 => 80). Forwarding privileged ports requires root access.

You could also accomplish this via firewall port-forwarding rules, as an alternative. SSH offers the benefits of authentication and encryption.