Rub the chicken thighs with the five spice powder and salt. Sear skin side down over high heat for about 3 minutes. Turn and sear the other side for 3 minutes. Place the chicken skin side up in the slow cooker. Add all of the sauce ingredients (except for the xanthan gum) to a small bowl and stir. Pour over the chicken in the slow cooker. Cook on high for four hours, or low for 6 hours. Remove the chicken from the slow cooker to a serving dish. Pour the remaining sauce into a magic bullet or blender and add 1/2 tsp xanthan gum. Blend for about 20 seconds. Pour over the chicken on the platter and serve warm. Cilantro garnish is optional.
Approx. nutrition info per serving: 392 calories, 23g fat, 3.5g net carbs, 37g protein