Make incisions with a sharp knife on the chicken breasts and set aside. Combine Kashmiri red chilli powder, ginger paste, garlic paste, hung yogurt, salt, lemon juice, garam masala powder and two teaspoons olive oil well. Apply this mixture to the chicken pieces and leave to marinate for three to four hours preferably in a refrigerator. Preheat oven to 200ºC/400ºF/Gas Mark 6.
Thread the chicken pieces onto skewers and cook in the preheated oven or in a moderately hot tandoor (clay oven) for ten to twelve minutes or until almost done. Baste it with the remaining olive oil and cook for another four minutes. When cool, shred chicken pieces and set aside.
In a large bowl combine shredded chicken, green, red and yellow capsicum strips, onion, green chillies, half the coriander leaves, lemon juice, chaat masala, raw mango (if using) and salt and toss to mix well. Transfer onto a serving plate and serve garnished with the remaining coriander leaves.