Let me tell you, there are more different kind of sand paintings than you (probably) think there are.
Most people think of only the kind that gets 'made' on glass with light under it. Now i say made with the ' because it doesnt actually get made. There are alot of pictures drawn on top of each other, and since its sand, the other one gets erased away.
There are two specific artists (that i know of) Who make paintings in the sand on large scale. And they don't erase it themselves, the tide does. Andres Amador and Jim Denevan are the guys who i'm talking about.
You can go look on his site for alot of videos and slideshows: http://www.andresamadorarts.com/ He even does Workshops. You can also buy 30 postcards for $23 (Around €18) and they are so beautiful!
I think this is the better version, maybe he is even the inventor? (I'm not sure) Much more info to find about him compared to the guy above. Also much more videos, just type in 'Jim Denevan' in youtube and there it is. Go take a look on his site for more beautiful pictures and more information about him and what he does. http://jimdenevan.com/
More on different kind of sand paintings in a later post.