Crispbread with raw spiced whitefish and cucumber

8 slices FINN CRISP crispbread
150 g raw spiced whitefish (European cisco)
1 small red onion
1 tbsp caper
1 tbsp dill       
1 tbsp sour cream
16 cucumber slices              
2 tbsp sugar
1 tbsp vinegar
salt, white pepper

Cube the whitefish and onion, spice with caper, dill, salt and pepper, mix with sour cream. Cut the cucumber into thin slices and mix with vinegar and sugar.