Probably pretty much the same build that was good for old Skarner. Either AS-onhit or AP-AS would be my guesses. I could see Guinsoo's Rageblade or Wit's End being a good core damage item, with Trimogma's to follow, or a little tankiness and then Deathcap, or something of that nature.
EDIT: Alternatively, Sheen is nice and cheap.