Peel the shallots and dice them very finely. Wash the cucumber, cut in half lengthwise, scrape out the seeds with a tablespoon. Finely dice the cucumber. Wash dill, shake dry and chop very finely. Wash chives, shake dry and cut into fine rolls.
Wash the lemon hot, dry and finely grate half of the peel. Cut the fruit in half and squeeze one half.
Rinse salmon, dab dry and remove any bones. Dice salmon very finely. Mix with shallots, cucumber, herbs, lemon peel and capers. Season well with salt, pepper and 1 pinch of sugar.
Stir in lemon juice and oil.
Break the crispbread into pieces, place on plates and spread the salmon tartare evenly on top. Serve with smooth stirred sour cream as desired.