In a medium Dutch oven or soup pot, warm the oil over medium heat. Add the onion, celery, carrots, garlic, and jalapeños. Sauté until the vegetables are tender, about 8 minutes. Add the water, tomatoes, beans, cumin, salt, quinoa, cilantro and cayenne pepper (if using). Season with pepper and bring the soup to a boil. Once boiling, lower the heat, cover the pot, and let the soup simmer until the quinoa is tender, about 15 minutes. Once the quinoa is tender, add more salt and pepper to taste, if necessary. You can serve this soup right away or use an immersion blender to purée a couple cups of this soup—this helps to thicken the soup while still leaving some texture (I may have overdone it a bit). Divide into bowls and serve with any garnishes that you'd like. Store leftovers, covered, in the refrigerator for up to 4 days, or in the freezer for up to 3 months.