Tomkins scored four tries, created two more and also booted 12 points as Super League leaders Wigan rebounded from their Challenge Cup exit last weekend at the hands of Leeds.
For Rea, it was a harsh lesson of the job ahead after stepping into the Broncos' hotseat earlier this week.
Wigan crossed twice in the opening seven minutes through Tomkins and Josh Charnley, before Tomkins grabbed his second as the visitors led 16-0 at the break.
It was one-way traffic again in the second period as Iain Thornley, Matty Smith and Brett Finch added to two more efforts from Tomkins.
Michael Robertson claimed a consolation for the hosts on 66 minutes, with Michael Witt converting.