i have no idea. i don't even know if it was on a beach. the detail on the skin textures is pretty amazing. if it is just beach sand they must humidify the tent. there are really big mullers, i guess you could use a cement truck, that would work to prep that much sand and put it on the beach. maybe they prep it with an environmentally friendly oil that bonds it together until it erodes back into the ocean. it looks suspicious the way it sticks to the tools. then again this is finland and maybe they don't have the EPA looking over their shoulder.
after a little research there are some people who use additives, sprays and other tricks to help these types of sculptures.
that and packing the shit out of it in the form.