What type of concrete foundation do you pour for sand?
There are multiple options for building on sand, but much of the answer depends on many other factors. Compact sand (to say sand cannot be compacted is erroneous, it just doesn't require much) can be a very stable base. We have built many homes, cottages and garages on land that is sand for 10s of metres deep. 

Screw piles are one solution that works, but all that does is point load your home onto the piles, so you need a lot of them. We have had no problems with thickened-edge slabs, frost walls on reinforced footings and even full basement foundations further from the lake. Just talk to a local engineer to get your footings and or piles appropriately sized.