1. Place chipotle and ancho chile peppers in a shallow bowl; pour in water. Cover the bowl and let sit at room temperature until peppers are softened, 10 to 12 hours. Drain water and remove seeds from peppers.

2. Blend chile peppers, red onion, garlic, sea salt, cumin, oregano, and black pepper in a blender until a coarse paste forms; add olive oil and blend until marinade is smooth.

3. Place chicken thighs between 2 sheets of heavy plastic on a solid, level surface. Firmly pound chicken with the smooth side of a meat mallet to a 1/2-inch thickness.

4. Place chicken in a resealable plastic bag and add marinade. Turn chicken several times to coat. Seal bag and marinate in the refrigerator for at least 8 hours.

5. Preheat an indoor grill with top and bottom plates for medium-high heat.

6. Remove chicken from the bag and discard marinade.

7. Place chicken on the preheated grill, close the lid, and cook until no longer pink in the center and the juices run clear, 5 to 7 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C). Cut chicken into strips and serve warm.

Tips

If you do not have an indoor electric grill, wrap a paver brick in aluminum foil and place it on top of the chicken to keep it flat while cooking on an outdoor grill.

Soak chile peppers in chicken broth instead of water, if desired.

Editor's Note:

Nutrition data for this recipe includes the full amount of marinade ingredients. The actual amount of marinade consumed will vary.