Take the first main left as you drive out of Port Ellen (signed for the Oa). You'll pass a wood on the left - turn left onto the track at the end of the trees. You'll see the beach about 200m in front of you.
Kilnaughton is not a beginners spot. It's a lovely beach but it's small and quite tight for launching. If you know what you're doing, you'll be alright but it would be easy to try a couple of things you can't nail and end up on the rocks at either end of the bay.
