Cover the kidney beans with cold water by 2 inches in a large pot. Let soak at least 8 hours and up to 24 hours. Drain.

Transfer the beans to the insert of a 6-quart Instant Pot®. Add 4 cups water and 1 teaspoon salt. Follow the manufacturer's guide for locking the lid and preparing to cook. Set to pressure cook on normal for 10 minutes.

After the pressure-cook cycle is complete, follow the manufacturer's guide for natural release. After 5 minutes, being careful of any remaining steam, unlock and remove the lid. Check to make sure the beans are cooked through and soft. If they're not cooked through, add 1 cup water and pressure cook for another 1 to 2 minutes.

Meanwhile, heat the oil in a large skillet or saucepan over medium-high heat. Once shimmering, add the cinnamon stick and cook until fragrant, 30 seconds to 1 minute. Add the onions and cook, stirring and scraping occasionally, until the onions are very soft and golden brown, 10 to 12 minutes.

Add the garlic and ginger and cook until the raw smell goes away, about 2 minutes. Add the chile powder, garam masala, sugar, turmeric and 1 teaspoon salt. Cook until the raw smell dissipates, about 3 minutes. Add the tomatoes and cook until thickened, 3 to 4 minutes.

Add the beans to the skillet along with ¾ cup of cooking liquid. Mix well and bring to a simmer over medium heat; simmer until the curry thickens and coats and flavors the beans, about 5 minutes. Add more water if needed. Season with salt to taste. Garnish with cilantro and serve.