I heard the place to go for Mexican food supplies is El Maiz, near Hauptbahnof so today that was my errand. It is pretty close to HB so I took the 31 bus and then walked to El Maiz on Josefstrasse.
The prices were a little expensive but this is Switzerland and to be expected. Still, I only bought white, distilled vinegar because I needed some for cleaning and I haven't seen it elsewhere. A small bottle was 3,50 CHF.
Other stuff you can find at El Maiz:
* A large variety of Mexican beer
* A larger variety of tequila
* Canned jalapeño peppers - many different kinds
* Fresh jalapeño peppers, tomatillos
* Many different brands of hot sauce, including Dave's Insanity Sauce for 14,40 CHF
* Wood tortilla press
* Piñatas, large ones
It is worth a stop if you are near the main Zurich train station.