In a medium saucepan, heat the oil over medium heat. Add the shallot, tomatoes, peppers and red pepper flakes and cook, stirring often, until slightly softened and aromatic, about 4 minutes. Season with the salt and add the quinoa. Using a wooden spoon, stir to coat the quinoa in the oil. Add the chicken broth, stir and bring to a simmer. Reduce the heat to low, cover the pan and cook until the quinoa is tender and the liquid is absorbed, about 20 minutes. Stir in the spinach to wilt and serve drizzled with olive oil.