Wash, peel, de-core and finely slice the apples into thin sticks. Don't worry that they're not all the same length since you'll be trimming them again later. Mix the apple sticks with the fromage frais (fromage blanc) and add salt and freshly ground pepper to taste.
Lay one quarter of this mixture, with the apple sticks all facing in the same direction, onto a slice of smoked salmon and roll the salmon into a tube. Wrap this in cling film and leave in the fridge for at least 15 minutes to help make cutting easier. Repeat with the other slices of salmon.
Remove the rolls from the fridge and remove the cling film, then cut into lengths of about 1" (2cm). Yummy...
** If you wish, you can substitute natural (unsweetened) yoghurt for fromage frais.