I'm interested to know the correct American English form of Würker.
Any general background information on this name's roots would also probably prove insightful as well.
Generally family names should not be translated, as they are genuine names that stand as they are. However in case we must it depends whether we wanted to transtlate the meaning (Metzger > Butcher, Bäcker > Baker, Müller > Miller), or if we wanted to find a name that is being pronounced the same.
The example name Würker offers both, as it likely derives from the Middle High German verb würken, which today became wirken in modern German and work in English.
Hence an etymologically correct transfer would be Worker, which would also be pronounced similarly in both, English and German.