1. Heat 2 tablespoons olive oil in a large pot over medium heat. Add onion and sauté until soft, about 5 minutes. Add jalapeño, garlic and ginger and sauté until fragrant, 1-2 minutes.
2. Add lentils, water and canned tomatoes with juice and salt. Bring mixture to a boil, then reduce heat and simmer unti soft, 30-40 minutes.
3. (Optional, if you prefer the texture) When lentils are soft and have begun to break down, mash with a potato masher to create a thick and creamy texture. Keep lentils warm.
4. In a small sauté pan, heat remaining 1 tablespoon of olive oil over medium high heat. When hot, add cumin seeds and mustard seeds and cook, stirring constantly, for 15 minutes. Add ground turmeric and paprika and continue to cook, stirring, for 30 seconds. Carefully add oil and spices to the lentils and stir to combine.