Not sure what part of the border you are coming from--I lived in San Diego for a long time and the Mexican food here is mostly disappointing but there are some decent options. El Patron and Pepe's are the only places in town that do a proper Cali burrito and it is surprisingly close. Shape is wrong and the tortilla isn't perfect but the ingredients are spot on. They are willing to do SD-style burritos in general (i.e. no rice and beans) you just have to ask; I have yet to try that though. They're also my go-to spots for tacos--good meats, proper toppings if you want (i.e. just cilantro/onions/maybe guac) and decent roja and verde sauces, but the tortillas aren't great. There aren't really good tortillas anywhere in the city.

Birria is a huge thing here and, much like New England IPAs, has completely overtaken the market.