In a small bowl, mix the turmeric with 1 tablespoon salt and 2 teaspoons pepper. Place the chicken on a rimmed baking sheet and sprinkle with the spice mixture, turning to coat both sides.
Heat a large skillet over medium-high heat and add the oil. Brown the chicken well on both sides, about 7 minutes per side. Pour in the water, then add the garlic, stirring it into the water. Bring the water to a boil, then turn down the heat to low and cover. Braise the chicken for 25 minutes, until the inside is opaque. Transfer the chicken to a serving platter, turn up the heat to high, and reduce the cooking liquid for a few minutes, stirring occasionally until it’s slightly thickened. Season to taste with salt and pepper, and pour the sauce over the chicken.
Dust the chicken with sumac and pepper, garnish with lime halves, and serve.
Heat the oil in a stockpot over medium heat and cook the onions for about 10 minutes, until they start to brown. Add the turmeric and corn. Pierce the limes with a knife or fork and add them to the pot along with their soaking water. Add the stock and bring to a boil. Cover and simmer for 15 minutes, until the corn is just tender.
Squeeze the limes against the side of the pot with a long spoon to extract their concentrated flavor before removing them from the soup. Blend half of the soup in a blender, then return it to the pot. Add the saffron and season to taste with salt and pepper. Add lemon juice to taste, and serve.