Combine all the marinade ingredients in a large bowl and blend until smooth. Add in the thighs and coat them well. Cover the bowl and refrigerate for 12-24 hours.
Combine all the chimichurri ingredients in a container and refrigerate until needed.
Heat up oil in a frying pan over medium-high heat. Place the thighs skin-side down and render the fat for 20-25 minutes.
Flip over and sear the other side for another 5 minutes. Remove from the pan and let the thighs cool off on a rack or a plate for 5 minutes and serve with your favorite side dish.