In a medium bowl, whisk together the smoked paprika through the cumin.
Rub 3/4 of the mixture into both sides of the chicken thighs and set aside.
In a large skillet, heat the oil over medium-high heat. Cook the chicken thighs for 2-4 minutes per side, or until the thighs are almost cooked through. Add in the onions and pepper and season with the remaining spice mixture.
Continue to cook until the peppers and onions are tender, and the chicken is cooked through. Remove from the heat and serve.