You can make the pearled barley and quinoa ahead of time, and keep covered and chilled in the refrigerator. Cooking the quick oats, and combining the oatmeal with the grains and other ingredients only takes a few minutes before serving.
Following the package instruction, cook the pearled barley over moderate heat in a medium saucepan for about 30 minutes, until tender. Using a colander, drain excess water from the cooked barley.
While the pearled barley cooks, use a small saucepan to combine the quinoa, 1/2 Cup of water and a pinch of kosher salt. Bring mixture to a boil. Cover and reduce heat to a simmer; cook until the water is absorbed, about 15 minutes.
The previous steps can be done up to several days ahead of time.
When ready to make breakfast, bring 2 Cups of water to boil in a medium saucepan. Add the quick-cook oats (and another pinch of salt), and cook over medium heat for 4 minutes (or according to package instructions), stirring continuously. When oatmeal is cooked, add the cooked barley and quinoa, Saigon Cinnamon, and half of the chopped dates, and cook, stirring, until mixture has thickened and is warmed through, about 3 minutes. Divide the cereal into four bowls. Top with a sprinkle of the remaining dates, and serve.