Yes, the web client is available only if you use vCenter and map your host to it.
Having said that, the symptoms suggest that VMware tools is not installed in the guest. Can you confirm / try reinstalling VMware Tools in the Virtual Machine?
Select VM > Guest > Install/Upgrade VMware Tools
To install a copy of vCenter Server 6.0, just go to https://my.vmware.com and request for a trial on VMware vSphere or VMware vSphere with Operations Management https://my.vmware.com/group/vmware/evalcenter?p=vsom#tab_download
After that, you can download vCenter Server 6.0.
The installation of vCenter Server 6.0 is quite easy, please remember to check the requirements such as:
- ESXi host
- ESXi host hardware requirements
- vSphere Client-Integration Plugin 6.0
- A web browser with flash enabled
well the trial will eventually expire ... is there an official free web interface I can install without messing with vCenter?
I have tried the experimental embedded web interface that is currently available on fling but while it looks nice, it lacks basic functionality (like power ON) ..
Yes, you can use the earlier mentioned host UI (http://www.vladan.fr/esxi-free-web-client-interface/ ) on a free ESXi, too.
With version 6.5, the UI is included in the normal installer. Before 6.5, you need to install the host UI yourself.
if you update you vSphere to either 6.5U1 or U2 or 6.7 there is a built in version of the fling mentioned by another poster. it will be more than adequate for a single host enviroment.