Heat the olive oil in a small skillet. Add the onions and saute for approximately 5 minutes, or until the onions are translucent. Add the garlic cloves and saute until fragrant, approximately 30 seconds. Transfer the onion & garlic to a slow cooker.
Add the tomatoes, black beans, bulgur, chipotle pepper, adobo sauce, cumin, chili powder, smoked paprika, salt, black pepper, and vegetable broth. Stir to combine.
Cover and set slow cooker to 4 hours on high or 6 hours on low.
Add additional salt if needed.
Enjoy with your favorite toppings!