In a skillet, brown the ground beef over medium heat until fully cooked.
Drain excess fat and transfer the beef to the slow cooker.
Add chopped onion and minced garlic to the slow cooker.
Pour in the crushed tomatoes and stir to combine.
Add drained kidney and black beans.
Sprinkle in chili powder, cumin, paprika, salt, and pepper.
Mix all ingredients well until evenly distributed.
Cover the slow cooker and set it on low for 6-8 hours or high for 3-4 hours.
Stir occasionally if possible, and check for seasoning adjustments.
Serve hot with optional toppings.