MEXICO CITY — Newly minted Michelin-starred chef Arturo Rivera Martínez stood over an insanely hot grill Wednesday at the first Mexican taco stand ever to get a coveted star from the French dining guide and did exactly the same thing he's been doing for 20 years: searing meat.
Though Michelin representatives came by Wednesday to present him with one of the company's heavy, full-sleeved, pristine white chef's jackets, he didn't put it on: In thi…