Heat the olive oil in a large saucepan over medium heat; cook the onion and garlic in the hot oil until the onions are translucent, 5 to 7 minutes. Stir the cumin, coriander, cayenne pepper, garam masala, curry powder and salt into the onion and garlic; cook together until fragrant, about 1 minute.
Add the potatoes, diced tomatoes, tomato puree and sultanas to the saucepan. Pour enough water over the mixture to cover; bring to a simmer and cook until the potatoes are soft, 10 to 15 minutes.
Add the chickpeas and kale to the saucepan; simmer until the kale wilts, about 3 minutes. Sprinkle the coriander over the stew and immediately remove the saucepan from the heat.