Firstly, finding a real authentic Mexican restaurant in Kitchener-Waterloo is impossible - they just don't exist. El Rinconcito Mexicano is probably as authentic as you get, and the food is incredible. Since we now live in Cambridge, we are about 10 minutes away from this restaurant, located on Ainslie street near Main in downtown Galt.
Secondly, real Mexican food is usually very Celiac friendly since a lot of it is made from corn flour. El Rinconcito Mexicano's menu has plenty of options: from corn tacos, enchiladas (made from corn) and also other options that are less known to me, such as gorditas. You have to stay away from the burritos and other items made with flour tortillas, but the two ladies that work there (I think mother and daughter) are very friendly and helpful if you can't understand the somewhat cryptic menu. (See below for what their menu looks like!)
All of the food is home made and cooked fresh. The prices are very reasonable: you can easily eat most of the dishes for $8 tax included. I've been twice now and had the enchiladas (with chicken) and also the soft tacos (I've tried chicken, pork and beef). I also had the gordita which was amazing. Although there are some standard drinks available (Coke, Sprite, etc.) many of their drinks are sodas from Mexico, like grapefruit or orange soda. Pretty cool.
Now, don't expect fine dining here. The decor is made up of a good mishmash of what looks to be garage sale items and old furniture from a student apartment. There are probably only about 5 tables, so if it's busy you're stuck with takeout. Here's a picture to illustrate:
But all of this adds to it's character, and quite frankly with food this good it doesn't matter what you're sitting on. It's clean - that's the most important point here.
Plus, if you ever need ingredients for your Mexican feast at home, the restaurant has also a few shelves of hard to find items such as corn flour, mole sauce (not GF), peppers and salsas from Mexico.
Well there you have it. Even though from Waterloo it's probably about a 30 minute drive, it's definitely worth the trip some Saturday afternoon for a great Mexican lunch! Enjoy.