Bring 5 cups of water and lentils to a boil in a covered 12 inch skillet. Reduce heat to medium and cook until the water is almost absorbed and the lentils are just tender about 12 minutes. (Note: I used green lentils and they took 20-25 minutes to cook.) Turn off heat.

Meanwhile, heat the 2 tablespoons of water or broth in a large dutch oven over medium heat. Add the onion and cook until tender, about 5 minutes. Add garlic, chili powder, cumin,  and cook until fragrant, about 30 seconds. Add the cooked lentils and canned tomatoes. Reduce heat to medium low and cook until most of the liquid has evaporated, about 5 minutes. Adjust the seasoning, including a generous sprinkling freshly ground black pepper.