In a large saucepan, bring the water and the lentils to a boil. Reduce the heat to medium-low, cover the pan, and simmer the lentils for 25-30 minutes or until the lentils are tender but not mushy. Do not overcook the lentils.
While the lentils cook, in a medium-sized skillet, preferably one with a nonstick surface, heat the oil, add the garlic, scallions, green pepper, cumin, and chili powder, and saute the ingredients for 2 minutes or until the vegetables are tender-crisp. Stir in the tomato sauce, vinegar, and molasses, and simmer the mixture for 1 minute.
When the lentils are cooked, add the vegetable mixture to the lentils, and heat the mixture through before serving it.