Garlic Shrimp Taco with Poblano Chile Rajas

I first tasted a variation of this taco at El Taco de la Ermita in Tijuana, where taquero extraordinaire Javier Campos served it dorado style with several of his magical salsas. In this simplified version, the delicious, smoky-rich flavor comes from the roasted chiles poblanos. Poblanos are wide and sharply pointed, with dark green, shiny skin. They come into their own when charred and sautéed with onions and garlic into rajas (literally, “rags”). Ripe red poblanos, als