How to I delete WINS name from Network > Advanced > WINS
Turns out that the solution was to 


Remove all the NetBIOS name entries in /Library/Preferences/SystemConfiguration/preferences.plist (there was one for every interface)
Killall -9 cfprefsd
Issue the 

sudo defaults delete/Library/Preferences/SystemConfiguration/com.apple.smb.server.plist

command for good measure.
Restart


I hope this can help others.