Heat olive oil in a large pot over medium heat. Add onion and cook until softened, about 5 minutes. Add garlic, chili powder, cumin, and smoked paprika and cook for 1 minute more.
Add vegetable broth, diced tomatoes, black beans, and corn to the pot. Bring to a boil, then reduce heat and simmer for 15-20 minutes.
Stir in cooked quinoa or rice. Season with salt and pepper to taste.
Serve hot, garnished with cilantro, avocado, and tortilla strips.