Yes it can Monitor VM's as well as even the ESX box it belongs too. Those SNMP settings are community strings set inside the OS. Obviously it is suggested to move them away from the defaults of things like "public", "private" or "Secret".
If SNMP is not configured on your server, we have a free tool which can help you do this, see here.
If you think SNMP is installed and setup then connect to the server and go to Services. If you see a service called SNMP Service, ensure it is running and right click on it and select properties. On the security tab are the settings about the community strings and whom to accept SNMP requests from etc.