A national dish is a culinary dish that is strongly associated with a particular country. A dish can be considered a national dish for a variety of reasons although many nations have favorite or popular dishes but not necessarily a national dish.
When a Middle Easterner or an Arab think of Mansaf, Jordan instantly comes to mind and same goes to the Egyptian dish Ful Mudammes and the Saudi dish Kabsah. So many of the Middle Eastern nations have their own national dish and some nations boast more than one as in the case with the Palestinian cuisine.
Of course, not all countries have a national dish and some countries share popular or favorite dishes as in the case with the nations of the Arabian (Persian) Gulf. Since this is not a food blog, we have no recipes to offer you but there are many food blogs and ton of websites that offer thousands of recipes.
Here are a few good food blogs: (some are no longer active but they have good archives)
Syrian Foodie in London
Turmeric & Saffron
Allrecipes - Middle Eastern Recipes
Hummus with Tabbouleh
Taste of Beirut
Orange Blossom Water