Add pork, onion, salt and sugar to a small pot and add enough water to cover about 1 inch above the pork.

Bring to a boil on high heat and then lower to medium and cook for about 25-30 minutes or until pork juices run clear when poked at the thickest part, or it registers 145 F with an instant read thermometer at the thickest part.

Cover the pork in a bowl as it cools so it doesn't darken. Once cool, slice the pork as thinly as you can to make rolling easier later.