At 6 p.m. on a Tuesday in July, Maskaras Mexican Grill, a popular restaurant in Dallas’s Oak Cliff neighborhood, is fairly empty. There should be a line of chatty customers waiting their turns to order during the dinner rush, but there are only a few people sitting at the red metal tables. A couple of laborers with dusty coveralls and muddy boots eat carne en su jugo (a Guadalajaran beef soup), and two parents attempt to wrangle their precocious children. While the restaurant is an Instagram-ready feast for the eyes, with lucha libre masks, photos of wrestlers, and a “Love Eat Tacos” sign on the walls, no one is snapping pictures or posing for a selfie. It’s eerily quiet.Behind the counter, co-owner Rodolfo Jiménez exhales…