Rinse quinoa thoroughly under cold running water. Warm oil in soup pot, add onions and salt, cover. Cook on medium heat for 5 minutes. Add drained quinoa, potatoes, peppers, tomatoes, veggie broth, and spices. Cover and bring to a boil. Reduce heat and simmer for 10 minutes. Add zucchini and simmer 15-20 minutes or until all veggies are tender. Stir in lemon juice.