Heat olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion and cook until softened, about 5-7 minutes.
Stir in the minced garlic, cumin, oregano, and red pepper flakes (if using). Cook for another minute until fragrant.
Add the drained and rinsed chickpeas, diced tomatoes (with their juice), and vegetable broth to the pot. Bring to a boil, then reduce heat and simmer for 15-20 minutes to allow the flavors to meld.
Stir in the chopped fresh spinach and cook until wilted, about 2-3 minutes.
Remove from heat and stir in the fresh lemon juice. Season with salt and black pepper to taste.
Ladle the soup into bowls. Garnish with chopped fresh parsley before serving.
Notes
This soup can be served with crusty bread for dipping. It also reheats well, making it a great option for meal prep.