Combine the cumin, salt, chilli powder, oregano, and cayenne into a small bowl. Mix and set aside.
Heat a large skillet over medium/high heat. Add the oil then the onions and cook onions until translucent, about 3 minutes. Add the garlic and cook for another minute or so.
Add the beef into the skillet and break up well. Continue to cook until browned. Add in the spice blend, mix in with the beef, and reduce heat to simmer. Add the water if needed to help the meat absorb the seasoning. The added water will evaporate away. Stir in the beans to heat through.