Press Sauté and add the olive oil to the Instant Pot. Once the oil is hot but not smoking, add the onion, curry powder, and ginger and stir just until fragrant, about 1 minute. Press Cancel to stop the cooking cycle.
Add the water and use a wooden spoon or spatula to scrape the bottom of the pot, making sure nothing has stuck. Add the sweet potatoes, carrots, lentils, salt, and a few grinds of pepper. Stir well to ensure the lentils are covered in water, then secure the lid and move the steam release valve to Sealing. Select Manual/Pressure Cook to cook on high pressure for 1 minute.
When the cooking cycle is complete, let the pressure naturally release for 3 minutes, then move the steam release valve to Venting. When the floating valve drops, remove the lid and add the coconut milk and kale. Stir until the kale has wilted, about 2 minutes. Taste and adjust the seasonings as needed, adding the maple syrup if you want a little sweetness.
Serve the curry warm over the grain of your choice and garnished with the cilantro. Store leftovers in an airtight container in the fridge for 1 week.