Drain and rinse beans; place in a large heavy pot and cover with about 1 inch of water or stock. Bring to a boil, skimming any foam, then add remaining ingredients. Reduce heat to a simmer and cook, stirring occasionally, until beans are tender; cooking time will vary depending on age of bean and variety. Cooked beans freeze well, so consider making a double batch.

For the Huevos: warm tortillas on each side in a lightly oiled skillet; do not toast. Wrap in a clean kitchen towel and keep warm in a low oven. Add a little more oil to the pan and add the salsa; heat, stirring occasionally, for about 5 minutes to thicken. Add black beans and cumin and cook for 2 minutes; taste and adjust seasoning.

Fry eggs to desired doneness in a little butter. Place a tortilla on a plate and top with beans and salsa mixture; top with remaining tortilla, garnish with remaining beans and salsa, and top with eggs. Garnish with cilaantro and crumbled cheese; salt and pepper if desired.