Osman Avila remembers watching his grandfather, Antonio Garcia, slicing the trompo for customers at the taco cart in front of his Monterrey, Mexico, home. As soon as Avila could walk, he was put to work handing out soda bottles and helping his cousins separate tortillas. At the age of five, Avila graduated to sweeping, and he later went on to peel tomatillos and remove jalapeño stems for the salsas. You could say he was born to be a taquero.It would take a couple more decades for him to embrace his fate, but now that he finally has, it is a thing of joy—although you must be at the right place at the right time to try Knight Out, the taqueria he owns with Mae Ann,…