Method:
Rinse quinoa under cold running water and drain. Combine water and quinoa in a medium saucepan and bring to a boil. Reduce heat to a simmer, cover and cook until quinoa is tender and all the water is absorbed, 15 to 20 minutes.
Meanwhile, heat olive oil in a large skillet over medium heat. Add onion and asparagus. Cook, stirring often, until asparagus is tender and bright green, 5 to 7 minutes. Add garlic and peas and continue cooking for another minute. Stir in chicken and cooked quinoa. Add the spinach and stir until it wilts, 3 to 5 minutes. Season with salt and pepper and serve immediately.