Heat 1 tablespoon vegetable oil in a saucepan over medium-high heat. Stir in rice; continue stirring until rice is coated with oil, about 3 minutes. Add 3 cups water and 1 teaspoon of salt. Bring to a boil; reduce heat to low, cover, and simmer until the rice is tender and liquid has been absorbed, 20 to 25 minutes.

Fill a large pot with lightly salted water and bring to a rolling boil over high heat. Stir in the macaroni, and return to a boil. Cook the macaroni uncovered, stirring occasionally, until the it has cooked through, but is still firm to the bite, about 8 minutes. Drain well in a colander. Return macaroni to cooking pot, cover and keep warm.

Soak lentils for 30 minutes. Drain and rinse; drain again. Bring 2 cups water to a boil in a pot and stir in lentils. Bring to a boil; cover and reduce heat to low. Simmer until lentils are tender 15 or 20 minutes. Stir in 1/2 teaspoon salt.

Heat 1 tablespoon vegetable oil in a large skillet over medium-high heat. Cook the onions in the oil, stirring often, until they begin to brown, 10 to 15 minutes. Onions should be a nice caramelized brown color. Add garlic and cook another minute. Remove from pan, drain on a paper towel-lined plate.

Place half of the onion mixture into a saucepan. Mix in the vinegar. Add the chopped tomatoes and tomato paste, black pepper, 2 1/2 teaspoons salt, cumin, and cayenne (if using). Bring to a boil then reduce heat to medium-low and simmer about 12 minutes.

Serve by placing a spoonful of rice, then macaroni, and then the lentils on serving plates. Sprinkle with some of the browned onions, then top with tomato sauce.