Combine all of the ingredients for the marinade, minus the dried chiles. Add the dried chiles to a pot of boiling water, reduce heat and continue cooking for 10 to 12 minutes. Transfer peppers to the blender along with 1 cup of water. Blend until smooth, strain out the pulp and add it to the mojo marinade. Taste for salt and pour over the chicken thighs and marinate overnight.
Prepare outdoor charcoal or gas grill for indirect heat. Remove chicken from marinade about 40 minutes before you are ready to grill, shaking off excess liquid. Transfer leftover marinade to a sauce pan and heat to a low simmer.
Brush the grates of grill with oil. Place the chicken thighs directly above the coals, skin side down, and sear on high heat for a few minutes. Transfer to indirect heat side of grill and continue cooking for about 2 hours or until temp. reaches 165 -175 degrees. Baste with cooked mojo sauce about every 30 minutes. Remove from heat and let rest. Yields 6 to 8 servings.