Add oil to a large soup pot over medium heat. Add green onion, poblano pepper, celery, and garlic. Cook for 4-5 minutes, stirring often.
Stir in potatoes, tomato paste, oregano, chili powder, 1 ½ teaspoon of salt, cumin, and coriander and continue cooking for 6-7 minutes.
Pour in broth, fire roasted tomatoes and lime juice. Bring the soup to a boil. Cover and reduce heat to medium low. Simmer for 25 minutes.
After 20 minutes, stir in the pinto beans and the cilantro. Continue cooking for 10 minutes. Taste and add up to an additional ¼ teaspoon of salt if desired.