Heat a large saucepan over medium heat. Add the coconut oil, onion, garlic, ginger, and chilis and fry for 2–3 minutes. Add the curry powder, cumin, and 1/2 tbsp of the turmeric. Continue to cook over low–medium heat for 1–2 minutes.
Cut each tomato into roughly 1/2 inch wedges. Try to retain as much juice as possible. Add them to the saucepan and cook for 1–2 minutes.
Add the stock, kale, and chickpeas, then bring to a boil and cook for 7–8 minutes.
While the curry is cooking, cook your buckwheat according to the package instructions. Stir the leftover turmeric into the water you're cooking in.
When the kale is tender, add the coriander and yogurt to the curry. Bring it to the boil, then remove from the heat. Serve over the buckwheat.