Do the 100 burpee challenge everyday for 2 weeks, LOL, that will bring out the abs if you can already kinda see them. Or just do some other form of HIIT, adjusting the diet of course helps but I can't give advice out on that one. I would imagine you would have to be fairly dialed in on how many cals you consume to cut just enough to bring fat levels down.
As for an Abs routine, I don't directly train them so I can't suggest one. But heavy front squats work well fro abs.