Stir together first 7 ingredients. Spread mixture on 1 side of 24 bread slices; top with remaining 24 bread slices. Trim crusts from sandwiches; cut each sandwich into 4 triangles with a serrated knife.
Pair with: Baumard Savennières or Oregon Pinot Gris.
These were great at a church reception. My plate was the first one cleared from the entire buffet table! My one alteration: I seeded one whole hothouse cucumber but didn't peel it. Then I grated it on the bigger holes on a box grater (directions from another cucumber sandwich recipe), rather than finely chopping the cucumber. I don't know why the picture shows sprouts, when they're clearly not in the recipe.