Michael,
I used to live in Hawaii. I only went to Kauai once (great island by the way) but there wasn't really alot of "flats" to fish from. That doesn't mean it can't be fished there is alot of reef around all of the islands with plenty of fish. I'd say most of the streamer patterns used for say bone fish and the like would be good. Hope this helps... Enjoy the island and check out the grand canyon of the pacific if you have time.
Mike