You are correct, you need a vCenter at a DR site that needs to be registered on the DR Avamar along with the proxy. Then you can login into the GUI and select the desired VM and perform redirected recovery.

Regards

Amol Powar

That's right approach, You can  register vCenter and Avamar proxy  with the DR Avamar grid, provided ensure that proxy at the DR site is registered with the DR Avamar server only, as proxy can be  active from only one of the Avamar grid  at a time.

I'm assuming I also would need to have at least one esx host registered to this vCenter at my DR site.  We have esx hosts already up there but they're registered with our main vCenter at our normal location. 

You can even register ESX host directly and perform recovery on it. You do not need vCenter explicitly, this will save some time if you need to recover couple of VM for emergency purpose. You may have to remove the ESX from an existing vCenter or deploy a fresh one

Note : If you register ESX as a vCenter than you won't be able to use proxy deployment manager to deploy a new proxy, you have to manually deploy one.

To register an esx server directly without vCetner, in Avamar Admin, do you just go to add a "Client Type - VMWare vCenter" and put in info for an esx host instead of a vCenter?

Correct

Just to add, make sure you register ESX in Avamar with same permission/account as that for vcenter.