Preheat the oven to 450°F and heat a large cast-iron skillet in it for 30 minutes.
Meanwhile, rinse the chicken under clod water and pat very dry, inside and out, with paper towels.Season the inside of the chicken's cavity with salt and stuff with the garlic, ginger and scallions. Truss the chicken by tying the ends of the legs together with butcher's twine.
Rub the chicken all over with 2 tablespoons of vegetable oil and season generously all over with salt and pepper. Remove the cast-iron skillet from the oven (careful, it's really hot!) and swirl in 1 tablespoon of oil; it will probably start smoking. Place the chicken, breast side up, in the cast-iron skillet and place in the oven.
Roast the chicken for 40 to 50 minutes, until the juices run clear when you poke the thigh with a sharp knife. While the bird is roasting, combine the gochujang and Frank's Red Hot in a small bowl. (That's your dipping sauce. We took this idea from Dale Talde. Dale knows what is up.) When the chicken is cooked, remove it from the pan and rest on a cutting board for 10 minutes. Serve with Quick Soy Sauce Pickles and Water Radish Kimchi.