1. Bring vinegar and 1 qt. water to a simmer in a pan over medium heat.
2. Meanwhile, spread muffins with butter. Top each with a slice of bacon.
3. Reduce heat under water to low. Crack eggs one at a time into a small bowl or ramekin and slip into water. Cook until whites are set but yolks are still runny, about 8 minutes. Using a slotted spoon, transfer eggs to muffins.
4. Top each egg with a slice of cheese and the salsa, olives, and green onion.