Some parts of the Sahara are below sea level and could therefore perhaps be used as a sea water storage area and for irrigation for salt tolerant plants. It would require a very long pipeline/canal system to channel the water to them. The same goes for the Caspian, Aral and Dead Seas which are well below sea level and becoming dessicated because of insufficient rainfall.
In Russia there is a general problem in that all the main rivers flow north - away from increasingly arid central/southern regions. Ideally the rivers should be reversed to facilitate irrigation.
The problem with all such major schemes is the energy cost of p building waterways and pumping systems to get water over intervening high ground. The best applications would appear to be desert areas near coasts with low lying land.
The effect of "greening" large areas of desert could be to ameliorate local extremes of temperature, create carbon sinks, and food/energy sources. It seems doubtful however that the overall effect on world climate could be anything but very marginal. Many deserts are also mountainous! "It's a mystery to me - the game commences, For the usual fee - plus expenses, Confidential information - it's in my diary..."
What happens to the salt that salicornia absorbs as part of the water it needs to grow.
A marine biologist would know better, but from what I do know, marine organisms do not have to have electrolyte concentrations that match the ocean. They can have metabolic processes that concentrate or expel various salts as part of their own homeostasis. The article did say that it was edible:
Known in some restaurants as sea asparagus, salicornia can be eaten fresh or steamed, squeezed into cooking oil or ground into high-protein meal.
