The below command can be used starting from server 2012 and up and it will list the WWN of a storage controller.
Server 2012 or higher
PortAddress is the WWN on this dual port FC adapter
Server 2008 or older
On older versions of Windows you can install fcinfo from Microsoft. Before going this route I would first open up MMC > Add Storage snap-in and see if you an get the WWN details from there or you can
FCinfo download link