Pour half the beans with reserved liquid into a blender and puree until smooth; set aside.

Heat olive oil over medium heat in a large, heavy-bottomed pot or dutch oven. Add garlic and cook for 1 minute. Add the chile powder, cumin, oregano, and cayenne pepper, and continue to cook for 1 minute more.

Add the remaining pinto beans, pureed beans, and vegetable broth to the pot. Stir to combine. Turn the heat to high and bring the soup to a boil. Once boiling, reduce the heat and let the soup simmer (without a lid) for 15 minutes. The soup will thicken slightly.

Season with salt and pepper to taste. Garnish with avocado and cilantro and serve with tortillas and lime wedges (optional).