Heat the olive oil in a large pot over medium heat. Add the onions, celery, red bell pepper, potatoes and jalapeno. Saute for 15 minutes or until potatoes are slightly soft. Then add zucchini, minced garlic, cumin, dried oregano, black pepper and salt; saute for 2-3 minutes. Add water and quinoa. Bring to a boil. Cover the pot, reduce heat and simmer until quinoa is cooked, about 15 minutes, stirring occasionally.
Remove about 1 1/2 cups of hot liquid from the soup and pour into a small bowl. Add peanut butter to hot liquid. Using a fork, blend well and make a smooth paste. Pour the peanut paste into the soup and mix well. Simmer for 10 more minutes. Add lemon juice, taste and adjust seasonings. Serve the quinoa soup hot. Note: If it's too thick, add more water.