Prep

1. The night before you cook, bring two cup of water to a boil. Remove from heat and drop in dried ancho chili peppers. Cover with a lid and let soak for 10 minutes to rehydrate.  Drain the now soaked chili peppers, split them open and rinse the seeds away. Place the rinsed peppers in a food processor (affiliate).
2. Next, open your cans of chipotle peppers and dump into a mesh strainer (affiliate) over a bowl.  Press through to drain only the adobo sauce into the bowl.  Dump sauce into food processor (affiliate) and discard peppers.  Next, add your red onion, cumin, garlic, oregano, salt and pepper.
3. Pulse in the processor until the mix begins to smooth. Then add your olive oil gradually until your mixture become a semi-fluid paste. Transfer to a large, gallon sized ziploc back.  Fill with your boneless, skinless chicken thighs and mix with your gloved hand until well blended. Seal the bag, pressing out any excess air and refrigerate overnight.

Cook

1. Heat an outdoor grill to about 375°. Oil your pre-heated grate and close for a minute to allow to preheat. Then, arrange your chicken over direct heat on the grill, fat side down. Cook for about 8 minutes, until the fat side has a nice dark brown-light black.  Flip and cook until the other side gets the same char, about 5 minutes.
2. Remove and let rest for 5 minutes on a wooden cutting board.  Dice the chicken into 1/2 inch chunks. Serve immediately on it's own, on top of freshly-cooked rice, or in some tacos or burritos.