Grilled Vegetarian Tacos with Chile-Lime Marinade

Prepare grill for medium heat. Whisk together first 6 ingredients, season with ½ teaspoon salt. Set marinade aside.
Grill the onion, poblano, bell peppers, portobello caps, and zucchini, turning every 3-5 minutes, until charred and tender, about 15-20 minutes total. Keep the portobellos top side down on the grill, do not turn. Portobello juices will accumulate in the face-up caps, be sure to save these umami-rich juices! You’ll use them in the next step.
Once cooled slightly, slice the root from the onion so the layers separate, add to a large bowl. Pour any accumulated juices from the mushrooms into the bowl, then slice the mushrooms, poblano, and peppers into ¾-inch wide strips. Keep the zucchini as they are, and add all of the vegetables to the bowl with the onion. Pour marinade over; toss to coat. Taste and season with additional salt.
Just before serving, grill the tortillas on low heat until just warmed through and pliable, about 15 seconds per side.
Fill tortillas with vegetables; serve with toppings.