Start the rice rinse before doing anything else as this can take up to 90 minutes. Place rice in a medium bowl, cover with hot tap water by 2 inches and let sit for 15 minutes. Using your fingers, gently stir the rice to release the starch. Pour off the water. Repeat adding and pouring off hot water until the water runs almost clear. Drain rice in a fine-mesh strainer. This can take 4-5 cycles.
Bring two quarts of salted water to a boil in a medium pan. Add macaroni and cook, stirring frequently, until al dente. Drain pasta, rinse with water to prevent sticking. Transfer to bowl and set aside.
Meanwhile, bring lentils, 4 cups of water, and 1 teaspoon of salt to a boil in a medium saucepan over high heat. Reduce heat to low and cook until lentils are just ender, 15 to 17 minutes. Drain and set aside.
Heat 1 tablespoon of the reserved onion oil in a medium saucepan. Add 1 teaspoon minced garlic, ½ teaspoon coriander, ½ teaspoon cumin, ¼ teaspoon cinnamon, ⅛ teaspoon nutmeg, ⅛ teaspoon cayenne, and ½ teaspoon salt and heat until fragrant, about 1 minute. Stir in tomato sauce and chickpeas, bring to a simmer, and cook until slightly thickened, about 10 minutes. Turn off heat, cover, and keep warm.
Heat 3 tablespoons of reserved onion oil in a Dutch oven. Add remaining garlic, 1 teaspoon coriander, 1 teaspoon cumin, ½ teaspoon cinnamon, ⅛ teaspoon nutmeg, ⅛ teaspoon cayenne and cook until fragrant, about 1 minute. Add rice and cook, stirring occasionally, until grain edges turn translucent, about 3 minutes. Stir in 2 cups of water and ½ teaspoon salt and bring to a boil. Stir in lentils, reduce heat to low, cover, and simmer gently until all liquid is absorbed, about 12 minutes.
After rice is cooked, turn off the heat and add the macaroni on top of the rice mixture. Cover with a clean dish towel and then a lid. Let sit for 10 minutes.
Return chickpea sauce to a simmer over medium heat. Stir in vinegar and season with salt and pepper to taste. Fluff rice, lentils, and macaroni with a fork, stir in parsley and half of the onions. Transfer to a serving platter, top with half of the sauce and remaining onions. Serve, passing the rest of the sauce separately.