Wash the cucumbers, cut off the ends. Cut the cucumbers in half lengthwise. Remove the seeds with the help of a tablespoon. Cut cucumber halves into three pieces (boats). Dice cucumber remains finely. Peel shallot and dice very finely. Mix quark, yoghurt and horseradish well.
Stir in cream. Season to taste with salt and pepper. Add the diced cucumber. Cut the salmon into small slices with a very sharp knife or break them up finely as you like. Fill curd cream with a tablespoon into the boats, spread some salmon on top and arrange on a plate. Serve garnished with lettuce, lemon and dill flags