In a medium saucepan of salted boiling water, cook the pearled barley over moderate heat for about 30 minutes, until tender.
Drain the barley in a colander and shake off all of the excess water.
Meanwhile, in a small saucepan, combine the quinoa, 1/2 cup of water and a pinch of salt and bring to a boil. Cover and simmer over low heat until the water is absorbed, about 15 minutes.
In a small, heatproof bowl, cover the dates with boiling water and let stand for 1 minute.
Drain the dates in a colander and let them cool. Peel and pit the dates and chop them into 1/2-inch pieces.
In another medium saucepan, bring 2 cups of water to a boil.
Add the oats and a pinch of salt and cook over moderate heat for 4 minutes, stirring constantly.
Add the cooked barley and quinoa, cinnamon and half of the chopped dates and cook, stirring, until thickened, about 3 minutes. Spoon the cereal into bowls, sprinkle with the remaining dates and serve.
