Heat the oil in a large frying pan. Add the onion and cook for 3-5 minutes or until soft and opaque. Add the chicken and cook for a further 10 minutes or until golden. Add the tikka sauce. Swirl out the jar with 2-3 tbsp cold water and add to the sauce. Bring to the boil, reduce the heat and simmer for 10 minutes, or until the chicken is cooked through.
Meanwhile, bring a saucepan of water to the boil and add the rice and cook for 10 minutes or according to pack instructions.
Mix the yogurt with the milk and cucumber.
Drain the rice and rinse with kettle hot water. Drain again. Place the rice in a serving dish top with the chicken tikka. Serve with the raita and poppadoms.