Rinse the quinoa well to wash away the saponin coating. (Saponin is a natural pesticide quinoa produces so birds won’t eat it. It doesn’t harm humans; it just makes the quinoa bitter if not rinsed well.)
Bring 2 ½ cups of water to a boil and add the quinoa. Cover and reduce the heat to low. Simmer until the water is absorbed, about 30 minutes. Just as with rice, do not stir—tilt the pan to see if there is any water left. Set aside.
Meanwhile, heat the oil in a large saucepan over medium flame. Add the onions and cook, stirring often until the onions are translucent, about 10 minutes. Stir in the paprika, cumin, and red pepper; cook and stir for several minutes.
Add the lentils, the tomatoes and 3 cups of water. Bring to a boil over high heat. Reduce the heat; cook and cook for about 30 minutes, stirring occasionally, adding more water if needed. The lentils should be tender to the bite.
Bring a pot of salted water to a boil. Add the kale leaves and simmer them until the greens are tender, 10 to 15 minutes.
Remove the kale from the water and let cool on a cutting board. Chop the leaves—about 1 inch apart with your knife in both directions.
Stir the kale into the lentils. Season to taste with salt and pepper. Serve over the steamed quinoa.