Try the lagoons at Ras Sudr (or Ras Sedr as locals call it). The place is one of the best in the world for kiting (IMHO).
The big lagoon there is of the size of Tampa Bay, all knee-deep crystal clear water. The West winds are 20-30 knt blowing pretty much 24/7 for the last few thousand years.
Ras Sudr has the whole infrastructure for kiting and windsurfing (shacks, kite gear, rescue watch, couple of decent hotels right at the beach).
It's a 4-5 hour drive from Cairo, you have to cross Suez canal (kind of scetchy experience with gazzillion of guards carrying their AK-47s watching tunnel exits) - if feasible, let a local driver go thru that.
