In a large saucepan, heat oil over medium heat.
Make a refrito by adding onion, pepper, tomato, garlic, cumin, salt, and half the cilantro. Cook until all ingredients have softened, about 3-4 minutes.
ring heat to high and add the water, bringing to a boil. Add lentils and reduce heat to low, cover partially and cook until the lentils are tender.
Remove from heat and add remaining cilantro as a garnish.
If you like things spicy you may want to add a bit of cayenne pepper to the dish along with the cumin. However, in Ecuador aji (hot sauce) is served at the table as a condiment so Ecuadorians can each add spice to their own liking.