Add the plantains to a pot of water with the water covering the plantains by 1-2 inches. Bring to a boil and let boil for about 30 minutes.
While the plantains are cooking, heat a pan over medium high heat with enough of the vegetable oil to cover the bottom of the pan. Once hot add in the onions and cook, stirring continuously. After 2 minutes, add in the vinegar and stir to make sure every slice of onion is well coated. Let simmer until soft, stirring occasionally, this should only take a few minutes. Remove from the pan and set aside.
Pour out the liquid from the frying pan and wipe it out. Add just enough oil to cover the bottom and heat over medium high heat. Once the oil is hot enough, add the salami, turn the heat to medium and fry until crispy on both sides. It should only take a few minutes per side.
Remove the salami from the pan or you can use another pan, but sometimes I want less dishes haha. Add some more vegetable oil to the pan if needed on medium heat and fry the cheese. You can lightly coat the cheese in flour or you can simply fry the cheese without. Fry until golden and crispy on both sides, about 2 min per side. Remove from the pan.
The plantains should be done by now. Drain all the water except 1 cup. Mash the plantains & water together with a potato masher. I like to add about 1tbsp of olive oil or butter as well to really get it smooth. I also will add a bit of salt and pepper.
Lastly, fry your eggs sunny side up. I usually do this in a nonstick pan over medium heat with 1 tbsp of butter. Fry until the egg whites aren't clear.
Serve everything together, usually the onions go on top of the mangu, eat and enjoy.