In a large pot over medium heat sauté the quinoa in the oil for about 6 to 7 minutes, until quinoa is lightly toasted. Add carrots, celery, and water and bring to a boil. Reduce heat and add chicken soup base, lemon juice, cumin, and pepper. Simmer uncovered until quinoa is tender, 15 to 20 minutes.
Add chicken, spinach, and scallions and cook until chicken is heated through and spinach is wilted. Season to taste with salt. Serve.