I've been eating Viennas since the 1980s, and they're easy but tasty. The basic recipe as I know it is a cheese and salad sandwich served on crusty French bread with a creamy dressing.
In Austria though it's dark crusty sourdough bread, and a fluffy filler. Many of the different spread recipes haven’t changed since the beginnings: bacon and egg, salami, wild sweet pepper, mushroom, onion and egg, gervais with carrot. The list goes on.
Feel free to chuck on any cold meats you fancy though. Sliced sausage such as pepperoni, salami, and chorizo are big favourites on the continent, or use bacon and chicken for a faux club sandwich. Ham and chorizo is a personal favourite of mine