Chicago has an unusually high number of extremely innovative and vegan-friendly Mexican businesses (Quesadilla, Azucar Bakery, La Cocina Logan Square, El Nuevo, and El Faro), beating out pretty much any other city. Quesadilla is the best of the bunch. This is a wonderful, mostly vegan Mexican joint run by a family from Mexico. As such, no complaints about the food being "inauthentic"---the food here is prepared with care and freshness.
Their "tinga" taco was fabulous and really cheap at less than $3 a piece---wonderfully spiced soy chicken and a simple garnish of cilantro and onions. This is exactly how a taco is served in Mexico, meaning open-face, and just meat and garnish. No beans, lettuce, cheese or whatever else.
Most of their tacos were good, but I think the tinga was the best, and the beef ones were a bit less flavorful.
The guacamole, however, wasn't quite as good as the tacos. It felt flat in terms of taste (maybe not enough cilantro and tomato?) and it was also much more expensive than anything else on the menu, despite being an appetizer.
Lastly, the chocolate cupcake (made by Azucar Bakery, a vegan Mexican bakery) was solid: moist, not too sweet, and nicely rich in chocolate flavor.
I can't wait to return to Quesadilla.