Drain and rinse beans. In a medium saucepan, heat oil to medium-high. Add onions and cook for about 4 minutes until softened but not browned. Reduce heat to medium. Add crushed garlic, chili powder and cumin and cook and stir for another minute. Add beans, salt and water. Stir and bring to a boil over high heat. Once boiling, reduce heat to a simmer and mash beans with a potato masher, leaving some beans whole. Simmer uncovered, stirring frequently, until desired consistency is reached. Add more water to thin if necessary. Salt to taste.