Wash the cucumber with hot water before topping and tailing it. Cut into thin slices lengthwise using a mandolin. Cut the chives into small tubes.
Pat the cucumber dry and spread with cream cheese. Sprinkle with chives and season with salt and pepper to taste. Cut the salmon trout into strips and arrange on top of the cream cheese. Roll up the slices of cucumber and secure with a toothpick if necessary.
Arrange the cucumber and salmon trout rolls on a plate and drizzle the lemon crema over the top.