Cut the cucumber in half, and scoop out the seeds with a spoon. Using a mandoline, slice the cucumber as thinly as possible. Sprinkle the cucumber slices with salt, and leave to render out its water in a colander.
Beat the cream cheese to soften to a spreadable consistency. Slather each slice of bread with the cream cheese.
Pat dry the cucumber with a paper towel.
Layer the smoked salmon on three slices of bread. Divide the cucumber slices amongst the three sandwiches, and top with the remaining bread.
Cut the crust off the sandwiches, and smear the edges liberally with the remaining cream cheese. Set aside until needed.
Split the cardamom pods, and extract the brown seeds. Heat a frying pan to medium high, and toast the cardamom, cumin and sesame seeds until fragrant. Coarsely grind the seeds in a mortar. Add the the pistachio nuts, and grind down until you obtain a rough powder.
Take each sandwich and roll the cream-cheesed-edges in the spice mix. Cut each sandwich into four triangles and serve.
«The ground spice mix can be kept for at least a week in an airtight container, and is lovely sprinkled on dips such as hummus and on grilled meats and vegetables.»