For the tartar sauce, first prepare the mayonnaise. To do this, put the egg yolks and mustard in the bowl of the food processor and gradually, SLOWLY let the oil stir in. Season well with pepper.
Cut the cucumbers into small cubes and put them in a bowl. Add the cream and stir with a spoon until smooth. Fold the mayonnaise into the cucumber and cream mixture and season well with salt and pepper.