are you talking about vcenter standalone converter to perform P2V, V2V or image builder?
Here is the windows based vcenter standalone converter
VMware vCenter Converter Standalone
Will that same converter perform the appropriate conversion for ESXi, and not just ESX?
I don't understand the conversion of ESXi.. these converters are used for virtual machine conversion. Could you please tell us what is your exact requirement ?
I am running ESXi 5.5, not fully ESX.
I have a virtual machine from a third party, that claims it's .vmdk format needs to be converted into my version of ESXi in order to load and run properly.
So I'm trying to idenfity if the vCenter stand alone converter will convert this third party's VM into a version that I can upload into the datastore on an ESXi 5.5 server, to run.
Yes, then you can try using this vcenter standalone converter.