Combine all dry spices in a bowl. Pat the chicken thighs dry with paper towels. Sprinkle chicken generously with the spice rub, using your fingers to press down so it sticks.
Whisk the yogurt and lime juice together in a small bowl. Thin with additional lime juice or a little water if desired. Set aside.
Preheat oven to 400 degrees. Heat a cast iron skillet over a medium flame. Place chicken skin side down into the skillet. Allow to cook until fat renders and skin crackles, about 8-10 minutes. When chicken releases easily from the pan, flip it over and transfer the skillet to the oven. Cook for an additional 15 minutes.
While the chicken is cooking, make the rice: Melt butter in a medium-sized saucepan over medium heat. Saute the shallots until soft. Stir in the rice and coat with the butter mixture. Pour in the broth, raisins and salt. Bring to to a boil, then reduce heat and simmer over low heat, covered, until rice is tender (about 15-20 minutes).
Remove chicken from the oven and baste with the juices from the pan. Stir the spinach leaves into the rice until wilted. Place chicken onto a bed of rice and drizzle with the citrus yogurt.