Prepare/preheat grill or grill pan to medium-high.
Drizzle garlic with a little olive or vegetable oil, season with salt and pepper and wrap tightly in foil. Grill until tender, 25-30 minutes, turning occasionally. Let cool then squeeze out cloves and paste.
Dress tomatillos, onion wedges and jalapeños with a little oil. Season with salt and pepper, and grill to blister and char all over; remove from heat.
Grill limes cut-side down to char and get their juices flowing.
Whisk up chili powder, 1 teaspoon each of cumin and coriander, half the grill-roasted garlic paste, the juice of 1 grilled lime and 3 tablespoons oil in a small bowl. Coat chicken in marinade and season with salt and pepper.
In a food processor, combine charred tomatillos, remaining half the grill-roasted garlic, grilled onion, 1 teaspoon cumin, cilantro, juice of remaining charred limes, honey or agave and the 2 roasted jalapeños (remove ribs and seeds for milder salsa). Process into a slightly chunky, saucy salsa and season with salt and pepper to taste.
Char tortillas to blister and blacken at edges and to soften. Wrap them in a clean towel to keep warm.
Grill chicken 10-12 minutes, turning occasionally. Slice chicken and serve with wedges of charred lime.
Assemble and arrange the fixin’s—the taco bar is officially open!