Heat the olive oil in a large skillet over medium-high heat. Add the onions; cook and stir until they start to become soft. Add the green peppers, red peppers, and garlic; cook and stir until vegetables are lightly browned and tender, the whole process should take about 10 minutes.
Pour the black beans into the slow cooker and set to Low. Stir in the vegetables and tomatoes. Season with salt, pepper, cumin, chili powder, oregano, vinegar and hot pepper sauce. Stir gently and cover. Cook on LOW for 6 to 8 hours.
Vitamin E – fat soluble vitamin that helps prevent oxidative stress to the body and other vitamins in the body