Score the chicken with a knife several times on each side, right to the bone. Mix the purée, curry paste, garlic, yogurt, ginger and vinegar in a large bowl. Add the chicken and toss to coat. Chill for 15 minutes, or up to 24 hours. Preheat the oven to gas 6, 200°C, fan 180°C. Arrange the chicken in a large, ovenproof roasting tin and spoon over the marinade. Cook for 35-40 minutes, until cooked through with no pink showing and the juices run clear. Meanwhile, cook the rice following the packet instructions and prepare the salad. Combine the cucumber and onion in a bowl and set aside. In another bowl, mix the yogurt, olive oil, mint sauce and white wine vinegar to make a runny dressing.