In a medium bowl, whisk together the olive oil, lime juice, lime zest, cilantro, garlic, cumin, salt, and pepper to create the marinade.
Place the chicken thighs in a large resealable bag or shallow dish and pour the marinade over them, ensuring even coating. Marinate in the refrigerator for at least 30 minutes.
Preheat a heavy cast-iron skillet over medium-high heat.
Remove the chicken from the marinade, allowing excess to drip off. Place the chicken thighs skin-side down in the hot skillet.
Sear the chicken for 5 to 7 minutes without moving it, until the skin is golden brown and crispy.
Flip the chicken thighs and continue cooking for another 8 to 10 minutes, or until the internal temperature reaches 165°F (74°C).
Remove the chicken from the skillet and let it rest for 5 minutes before serving.