Here in Fresno, CA, we have a plethora of authentic mom & pop Mexican food places.. there are actually 4 of them within a half mile of my house! Not all the new places that pop up, survive, because even though one is "authentic", one has to be top notch because you are competing with others just as "authentic". Some of the best include:
Mario's on Divisidero. Home of the kitchen sink nacho plates. House made chips smothered in Chili Verde, housemade salsa, guacamole, mexican sour cream, Jack cheese, and some sort of secret "chili sauce".
Robertito's, a Fresno legend. A popular local chain with homemade tortillas and awesome burritos of every stripe. Watch out for their 5 alarm chile verde! Open 24/7.
Alberto's, another local chain with the most succulent carne asada around.
Don Pepe's. A little hole in the wall joint with ice cold cerveza and great tortas (Mexican sandwiches). This place is full to the gills every lunchtime. Favored by the local Fire Dept. Don't forget to visit their condiment bar!
All the places I've mentioned have drive thrus except Don Pepe's. Don's is indoor eating and takeout, Robertito's and Mario's have limited outdoor and indoor seating. The Alberto's on Willow not only has ample indoor seating but a large children's play area!
And this is just the beginning.. there are dozens more, where you'd swear you'd crossed the border!