Wash the sweet potato and cut it with the skin into equal pieces. Bring a pan of water to a boil, parboil the potato pieces for five minutes and drain. Meanwhile, rub the chicken thigh fillet with the ginger powder and some of the black pepper.
Heat the coconut oil in a frying pan and cook the parboiled sweet potato pieces with the turmeric and remaining black pepper until golden brown. At the same time, heat a grill pan and grill the seasoned chicken thigh fillet for about six minutes per side until cooked through. Meanwhile, steam the green beans for four minutes until tender-crisp.
Mix the tahini with the apple cider vinegar in a small bowl. Add a splash of warm water to this and stir vigorously until a smooth, liquid sauce forms.
Arrange the steamed green beans and the roasted sweet potato on a plate. Place the grilled chicken thigh fillet on top of the vegetables and drizzle the dish with the tahini sauce.