Just as the best way to test a sushi chef's skill is to order the rolled omelet, the best way to test a taqueria's mettle is to get a regular carnitas burrito, in which it's impossible to hide flaws with fistfuls of melted cheese. This bare-bones taqueria on the eastern end of the 24th Street strip, which still prices its basic burritos at $5, gets everything right. The balance of beans to meat to rice is perfect; there's no need to keep rotating the burrito, searching for the right angle of attack. A pleasant smell of toasted lard rises up when you bite through the tortilla (griddle-warmed, FYI), flanked by the sharper scents of green chiles and cilantro. Superburrito lovers who can't imagine life without heavy doses of sour cream and guac may take a bite and think, meh, where's the thrill? That's when they should slide over those plastic tubs of Taqueria San Francisco's salsa fresca and throbbing, spice-drunk salsa roja, and turbocharge.