Editor’s Note: Watch CNN Original Series “Eva Longoria: Searching for Spain,” following the award-winning actress on a gastronomic pilgrimage across the rich tapestry of Spanish cuisine. Sunday nights at 9 p.m. ET/PT on CNN. CNN  —  Is there a food more humble yet universally adored than the sandwich? And while one person’s go-to hamburger snack might be another’s katsu sando or chivito, there’s hardly a country on the planet that doesn’t turn to some type of bread with something stuffed inside