1. I am assuming that a users has to have an account on the VMware server to be able to remote access into a virtual server??
No, this is solely a Windows OS thing.
2. If so, how do you setup a user and give them rights to just that one virtual server?
You setup groups under remote settings of the guest. If a user is a member of the local administrators group they have RDP access by default.
If I misunderstood your question, can you elaborate a bit?