How to stop splashing from above counter sinks in bathroom?
If you mean a sink that's sunk into a counter top, it's next to impossible not to splash the surrounding area when you use it. It helps if the sink is a good size and deep, but sadly, many modern sinks aren't, so if you've got a designer type 'sink' that's more like a shallow tray (like one I saw recently in a friend's house), then you need to keep a towel on hand specially to clean up water splashes afterwards. I'm afraid those type of sinks are more for looking at than using, definitely a case of appearance, design and form over function.
The most common cause for excessive splashing from your sink is how the water comes pouring from the tap, our taps are generally simple-crafted ones that release the water in floods. The best way to resolve this issue is to invest in a tap aerator, these break up the flood of water in the same way ordinary shower heads do.
The tap aerators usually come with the regulator to fit them with too which isn't difficult to do.
I found this one here.
Hope this helps!