Cut the Chicken into 1 1/2" chunks and marinate with salt, chilli powder and lemon juice, keep aside. Grind the Coriander, mint & Spinach leaves to a fine paste. Mix this paste with dahi, cream, ginger and garlic pastes and the garam masala. Mix the paste with the Chicken & leave in the fridge overnight. Remove from the fridge atleast one hour before cooking. Grill the Chicken pieces on skewers or a grilling tray basting over with oil. Cook until chicken is tender & browned on all sides. Serve hot with chutney & onion rings.