4 dried guajillo chiles (about 1 ounce)
1 dried ancho chile
2 dried chipotle chiles
2 tablespoons fresh orange juice
1/2 tablespoon fresh lime juice
3 tablespoons cider vinegar
1 teaspoon anntto seeds
1/2 teaspoon dried oregano
1/4 teaspoon cumin seeds
1 whole clove
1/2 tablespoon honey
1/4 teaspoon garlic powder
2 1/2 pounds boneless skinless chicken breast, cut into 1/2-inch-thick slices
2 tablespoons vegetable oil, plus more for grilling
1 large Spanish onion, cut into 1/2-inch-thick slices
2 cups diced zucchini, roasted
Salt and freshly ground pepper
12 corn tortillas made with Whole Corn, warmed
crumbled queso fresco
Cilantro, for serving
1. Stem and seed all of the dried chiles and place them in a microwave-safe bowl. Cover with water and microwave at high power until softened, about 3 minutes. Let cool slightly, then drain and transfer to a blender. Add the orange juice, lime juice, and vinegar. In a spice grinder, grind the annatto with the oregano, cumin, clove, honey and garlic powder until fine. Add the spice mixture to the blender and blend until smooth.
2. Transfer the marinade to a saucepan. Add the 2 tablespoons of oil and cook over moderate heat, stirring constantly, until very thick, about 5 minutes; let cool.
3. Transfer the marinade to a large resealable plastic bag. Add the chicken and onion and seal the bag. Refrigerate overnight.
4. Light a grill. Remove the chicken and onion from the marinade and scrape most of it off. Brush the chicken and onion with oil and season with salt and pepper.
5. Grill over moderate heat, turning, until the meat is cooked through, 15 minutes. Transfer the chicken and onion to a work surface, cover loosely with foil and let stand 10 minutes.
6. Cut the chicken into strips. Serve the chicken and onion and zucchini with the warmed tortillas, tomatoes, queso fresco and cilantro.