In a large saucepan, heat oil and begin to sauté onion. Cook until softened then add salsa. Stirring occasionally, simmer for 5 minutes to concentrate flavors. Add chicken broth and simmer for 10 minutes to meld the soup flavors. Add chicken, hominy, and black beans. Continue to cook until all ingredients are cooked through. Season with salt and pepper to taste. Ladle soup into bowls and garnish with fresh vegetables and herbs.