Place the cumin, peppercorns, coriander seeds, chillies, turmeric, and salt in a mortar and pestle and grind until it forms a powder.
Use a small sharp knife to slash the skin of the chickens.
Brush with the oil and rub in the cumin and sea salt rub. Place the chicken, skin side on a baking tray and roast for 30 minutes or until the skin is golden and crispy and the chicken is cooked through.
Serve with your favourite blanched greens and truss tomatoes.