Preheat oven to 350 ℉. Blend all of the spices (cumin, oregano, paprika, salt and pepper together in a small bowl).
Pat dry the chicken using a paper towel and season with spice blend on top and bottom.
Heat oil in a large (12-inch) skillet over medium-high. Place the chicken skin-side down in the skillet and sear for 7 to 9 minutes, until crispy, golden and the skin easily releases from the bottom of the skillet. Flip the chicken thighs and continue cooking for 5 minutes, until golden brown. Transfer the seared chicken to a baking dish, skin side up. Set aside.
Add the shallots, decrease the heat to medium. Cook, stirring frequently, until translucent and soft, and beginning to caramelize.
Add 1/2 cup of the combined olive brine juices to the skillet and scrape to loosen the brown bits from the bottom of the pan. Add all of the olives and saute for about 5 minutes. Then, add the tomatoes, cover, and continue to cook for another 4-5 minutes.
Transfer the shallot, olive and tomato mixture and all of the juices on top of the chicken thighs in the baking dish. Bake, uncovered for about 35 minutes. Increase oven temperature to 400 ℉ and continue to bake for another 15 minutes, or until the thighs are fully cooked.
Serve chicken onto plates and spoon a healthy amount of the tomato, olive and shallot mixture over each. Distribute any remaining evenly over each serving.