In a small bowl, mix together the paprika, cumin, garlic and onion powder, salt, cayenne pepper, and oil.
Place the chicken on a plate or in a bowl, and pour the spice mixture over top. Toss to fully coat. Allow to sit at room temperature for at least 20 minutes or up to an hour.
Heat a lightly oiled skillet over medium heat and sauté the chicken until the spice rub looks golden and crusty and the chicken is just cooked through the center, about 8 minutes on each side depending on the thickness of the fillets. Flip with tongs after the first 4-5 minutes and then after another 4-5 minutes on the second side. After that, flip occasionally to avoid burning until the chicken is done.
For juicy, tender chicken, the internal temperature taken with a quick-read thermometer should read about 160 degrees F. The temperature will continue to rise to the recommended 165 degrees F as the chicken rests for 5-10 minutes before serving. Slice on the diagonal, if desired, and serve.