In a large bowl, whisk garlic, lime juice, cilantro, cumin, red pepper flakes, and 2 Tbsp. oil. Add chicken and toss to coat. Cover bowl and refrigerate at least 30 minutes and up to 2 hours.
Arrange a rack in center of oven; preheat to 425°. In a large ovenproof skillet over medium-high heat, heat remaining 2 Tbsp oil. Season chicken with salt and pepper, then add to skillet skin-side down and pour in remaining marinade. Cook, undisturbed, until skin is golden and crispy, about 6 minutes. Turn and cook until other side is golden, about 2 minutes more.
Transfer skillet to oven and bake until chicken is cooked through and an instant-read thermometer inserted into thickest part registers 165°, 10 to 12 minutes.
Divide rice among bowls. Drizzle with pan drippings.