Heat oil in a heavy cast skillet over medium high heat until very hot. Season chicken with salt and sear 4 thighs skin-side down until golden brown, about 5 minutes. Remove chicken from the pan and add to the crock pot, skin side up. Repeat with the 4 remaining thighs.
In a blender or food processor, add the gochujang sauce, soy sauce, ginger, garlic, sesame oil, brown sugar and water. Blitz into a sauce and pour evenly over the chicken. Put the lid on the crock pot and cook on low for 3 hours, or until the chicken is cooked and tender.*
Top with sesame seeds and scallions. I suggest you serve this with white rice and sautéed spinach, kale or zucchini.
