To a large pot, add can of light coconut milk, 2 cups water, lentils, and potatoes. Bring to a boil, then lower heat until simmering and cook uncovered until potatoes are tender, the lentils are soft, and most of the water is absorbed, about 20-25 minutes, stirring occasionally. Remove from heat.
Meanwhile, to a high-powered blender, add the 3 tomatoes, onion, bell pepper, garlic, ginger and 3 tablespoons water. Blend until smooth (you may need to stop the blender and press down with a large spoon if the blade doesn't spin, but once it catches some of the tomatoes, it will quickly puree into a liquid).
Transfer liquid to a large skillet over medium heat (using a spatula to remove the remaining liquid off the sides of the blender, if necessary). Bring to a low boil and simmer until you can no longer smell raw onion, about 6-7 minutes, stirring occasionally.
Reduce heat and add the peas, coriander, cumin, turmeric, cinnamon, black pepper, and salt. Stir and cook for 2-3 minutes. Add the cooked lentils/potatoes to the sauce. Reduce to low heat and warm for an additional 2 minutes, stirring often.
Remove from heat. Stir in the lime juice and cilantro and let sit for 10 minutes before serving to absorb flavors. Serve with naan bread and/or brown rice and sprinkle with remaining lime juice.