How to cook Frijoles Charros mexican style?

1 to 2 onions, minced
2 tablespoons lard
3 cups cooked pinto beans
4 to 6 slices bacon, minced
1 slice ham, diced (optional)
½ cup chorizo or hot italian sausage
1 16−ounce can tomatoes, drained and chopped
6 serrano chiles, minced, or to taste
1 tablespoon comino (cumin)
salt to taste

Add onions and lard to pinto beans and cook over medium heat 5 minutes, stirring occasionally. in another skillet, fry bacon, ham and chorizo. Add to beans with tomatoes, chiles and spices. Heat thoroughly.