It is a daunting task, trying to anoint one taqueria that serves the best burrito in San Francisco. It’s almost a mission meant to end in defeat when one thinks of the sheer volume of celebrated taquerias in the famous Mission district alone. Even as I posted a teaser on Instagram about my San Francisco Burrito Quest, suggestions started to come in from Oakland . . . and the East Bay is its own beast, worthy of a separate “best ...