If you get the chance then I highly recommend arranging a lift and doing a downwinder from Speed Spot to the White Dune. You could leave from main lagoon area and go upwind from Dakhla Attitude although that would take a lot of the fun out of it. At high tide the waterline approaches the road to the north of Speed Spot where it is very shallow and super flat. You can zip across to the far shore which is about 4Km at incredible speed. Just be careful not to stack it in ankle deep water! From there you can follow the coastline all the way down to the White Dune, a crescent sand dune (see photo above) which gets completely cut off from the mainland at high tide.