Peel the onion. Finely dice it. Rinse the chilli. Halve it. Flick out the seeds and white bits. Finely slice it. Peel the ginger and garlic. Grate them both. Rinse the kale. Finely shred it, throwing away the thick middle core. Fill the kettle and boil it.
Heat 1 tbsp oil in a deep frying pan or wok. Add the chicken. Season with a little salt and pepper. Fry and stir for about 5 mins till it's golden all over. Pop on a plate. Put to one side.
Add the onion to the pan. Fry gently over a low heat for 5-8 mins till soft. Stir every now and then. Stir in the chilli, ginger and garlic. Cook for 1 min. Add 1 tsp each of the cumin and the smoked paprika. Cook and stir for 1 more min.
Add the chicken, the chopped tomatoes and half a sachet of the spice mix. Half fill the tomato tin with water. Pour into the pan. Pop on the lid. Simmer for 10-15 mins over a medium heat till the sauce has thickened a little. Stir every now and then.
While the sauce cooks, tip the rice into a pan. Pour 250ml hot water from the kettle. Cover. Bring to the boil. Turn the heat down. Simmer for 6 mins till the water has been absorbed. Take off the heat. Steam, lid on, for 2-4 mins till the rice is cooked.
Stir the kale into the sauce a handful at a time. Allow each handful to wilt before adding more kale. If the sauce seems too thick, add a splash of water.
Taste and adjust the seasoning, Let the sauce warm through for 2-3 mins. Serve the chicken tikka masala with the rice.