I know this is a whole other topic, but I can hone a naniwa with 600 grit on my granite countertop? sounds easy....this may be a good choice for me
It'll make a mess (you should keep the sandpaper flooded with water), but it should work OK. If you have a wife who cares about the kitchen, I'd suggest buying a tile rather than risking the kitchen counter. I use a marble (maybe granite) tile, cost $10 at Home Depot.

Charles