Best Mexican Hole in the Wall
is in Highland/Cypress Park. Yes, this is my favorite (Mexican) Restaurant.
La Abeja takes cash only and is closed on Tuesdays. Don't get there after 2:30 on a Sunday, or 1:30 on a Monday; They are getting ready to close. Open till 8 pm otherwise (new hours as of a few months back or so, still has me super excited)
This is hands-down, THE BEST Mexican food ever. The place looks and feels very homely, and the food will have you comatose by the time you get back to your place.
Cheap Burritos and excellent combo plates; what more could you ask for? Will upload photos when I get the chance.
Never been to La Abeja, so I can't offer an opinion on that. But I would like to chime in and say that if your criteria for the best mom and pop Mexican food is cheap burritos and combo plates that leave you comatose, then you need to spend some more time reading Chowhound, my friend! This is Southern California, not Omaha... Boyle Heights is a stone's throw away.
I don't know if it's the best mexican food/hole in the wall in the area---there are lots of others as well. Fig from the LA river bridge all the way to York has lots of decent mexican food---from stands, to fast food, to sit down family places. If I was going for a sit down family sort of spot, I would pick Las Fuentes over La Abeja.