Prepare the cucumber by julienning it and mixing with vinegar and sugar for a sweet and tangy flavor. Pat dry the bell pepper slices with a kitchen towel.

Spread strawberry jam, mayonnaise, mustard sauce, and butter evenly on each slice of bread.

Trim the crusts off the bread and microwave briefly to soften. Use a rolling pin to flatten the bread slices.

Layer ham, cheese, bell pepper, and cucumber on the flattened bread. Roll tightly using a sushi mat and wrap with cling film to secure.