I was totally creeped out by El Charro when I first went in there. Super dark (like, you seriously cant see in there for about 5 minutes when you first walk in and are literally blinded by the AZ sun when you come back out), cold, and at the time SERIOUSLY smoky (but not anymore). Its very small and cave-like, but dont let the weird ambiance deter you from trying this mexican joint.
I always have the cheese tea, which is just a cheese quesadilla so I dont know why they have this odd name... They also have the mexican cheese tea which is filled with cheese and beef. Its lathered in butter so be prepared to hit the gym afterwards, but its worth it. The burritos are good too, and surprisingly I hear they make an exceptional cheeseburger.
Be forewarned, El Charro closes for three months in the summer, so call for open hours.