Suction Cup Light Night Paddling
http://stokemagazine.blogspot.com/2012/01/suction-cup-light-for-sups-kayaks.html
I use one occasionally
I have one more or less like the one in the link. It works great. I place it on the rear deck so not to interfere with my vision.
2 Versions we have and like
Paddlers supply and Kayalu - led lights.