When we got to Annie's Annuals up in Richmond, my wife got really hungry, so we turned around and headed to a taco truck we saw on the way there, just a few blocks away.
It's in the parking lot of a very nondescript strip mall with a supermarket and a few stores. They had a few different kinds of meat burritos on the menu (including lengua and cabeza if that's your thing), quesadillas and tacos.
I shelled out $10.50 for a chicken burrito, a quesadilla for the tots, and a veggie burrito for my wife (they don't really have one on the menu, I just asked for 'no meat'). I wouldn't have minded avocado or a bit of chopped cilantro but at those prices I'm not complaining. I've spent that much for a drink and a burrito that didn't taste nearly as good at Picante.
I think the best part of it is the rice (very tasty and not dry) - the salsa was yummy too. And so were the chips (often times you go to a taqeuria and the burrito is good but the chips are lame...) I think we went at a good time too, it was early (11:30) for lunch, so everything was really freshly cooked, and after we got our order there was a line of people.
I haven't been to too many taqueria trucks (I think I read about one in fruitvale that was good). I went to one near golden gate fields that was just ok. So maybe my expectations bar was set pretty low, but the Los Grillenses truck was as good as any burrito I've had in the East Bay.