In a large skillet, over medium-high heat, heat the olive oil. Add the chopped onion and red pepper. Saute the vegetables for 4-5 minutes, just until the onions are translucent. Add the minced garlic and stir for 1 minute, until the garlic is fragrant.Pour the black beans into the crock-pot, followed by the the pepper and onion mixture. Add the chopped cilantro, salt, and water/broth. Stir the soup ingredients to combine. Cook the soup in the crock-pot for 8 hours on low or 4 hours on high.Serve warm with fresh cilantro, sour cream, rice, tomatoes, cheese, avocado, or salsa. You can also drain a portion of the beans to use for nachos (an easy recipe is coming soon), quesadillas, or tacos.