Locals can be spotted eating at pop up taco stands between Cancun International Airport and the mainland city of Cancun Proper.  Some of the best tacos and tortas are found here. and in stalls at Mercado 23 in the center of Cancun.  Easily spotted on the drive, many vendors are set up mornings to evenings and you can tell which are the better ones by by seeing the number of vehicles pulled off to the side. A lot of the airport personel and transportation workers eat here on a daily.  The prices are right and the tacos are as good, if not better, than the restaurants and stalls.  Try them with the various toppings of pickled onions, salsa verde, and some of the cabbage chili with your taco! Moi Bien!