Whisk together the adobo sauce, vegetable oil, minced garlic, lime juice, chili powder, cumin, oregano, salt, and pepper in a large non-reactive container.
Submerge the chicken thighs in the marinade, ensuring complete coverage of all surfaces.
Seal and refrigerate for 4 hours to facilitate flavor absorption and acid-driven tenderization.
Preheat a cast-iron griddle or grill to medium-high heat (approximately 400°F/204°C).
Place chicken on the cooking surface and sear for 7 to 9 minutes per side until a caramelized crust is achieved.
Verify an internal temperature of 165°F (74°C) using a calibrated digital probe thermometer.
Rest the chicken for 10 minutes on a room-temperature surface to stabilize internal juices.
Dice the rested chicken into uniform 1/2-inch cubes for service.