What is the name of this feature on the Red Sea coast of Saudi Arabia?
The area you describe looks like the following (from Google Maps):



According to the World Atlas of Coral Reefs, a picture of this very reef appears on page 240.  The caption for it describes the feature as being the Al Wadj Bank and consisting of fringe and barrier reefs.

There has been a relatively recent study of coral reefs along the Saudi Arabian Red Sea coast, of particular emphasis on reefs between the cities of Haql and Yanbu, published in the paper The Present Status of the Red Sea Coral Reefs between Haql and Yanbu, Saudi Arabia (Hariri, 2012).
In the article, they describe that in terms of Red Sea reefs:


Island fringing reefs exist between the Al Wajh Bank to Umluj
Reticulate patch reefs, composed of interconnected networks of reef matrix separated by sand also are documented to occur in the area.


The literature seems to use both Al Wajh and Al Wadj for the spelling.