Rinse the lentils in a strainer and set aside to drain. Place the diced tomatoes, chiles or peppers, onion, garlic, ginger, spices and salt in a food processor or blender and blend until a smooth paste forms.

Pour the coconut milk, water, and blended tomato mixture into a medium saucepan, stir to combine, and bring to a boil over medium heat. Stir the rinsed lentils into the coconut milk mixture, turn the heat down to low and simmer, covered, until the lentils are tender but not falling apart, about 25 minutes. Once the lentils are cooked, remove from the heat and stir the spinach leaves into the lentils, allowing them to wilt slightly. Taste for seasonings and add more salt, if needed. Serve lentils immediately with rice, freshly chopped cilantro and/or warm naan.