Topwater swimming-type plugs (Rapalas, Rebels, ZoYuri's, etc.) work well off the jetties during the incoming high tide.
Hot tip - Fish the night high tide and use black or black/purple combinations. For daytime use on the jetties, try the "schoolbus" color.

Other tips in the Hot Spots section for Delaware.
...And make sure you wear your Korkers and PFD on the jetty! One slip, and you're downstream in that current!
