You SSH into the storage controller's mgmt IP address that should be in the same subnet as the ESXi mgmt IPs.
You will generally login as root unless it's a new deployment and then the default account will be 'admin'
If you aren't sure what the ip of the storage controller is, try running the following on the ESXi host, cli:
/opt/springpath/support/getstctlvmip.sh
which should return mgmt IP of the storage controllers eth0 interface.
Kirk...