Place the softened cream cheese and mayonnaise in a small mixing bowl.
Using a hand mixer, whisk until the mixture is smooth and evenly combined.
Add the chopped fresh dill, chopped green onions, lemon zest, lemon juice, garlic powder, and onion powder.
Season with salt and pepper to taste.
Stir until all herbs and seasonings are fully incorporated.
Spread the cream cheese mixture evenly over the bread slices.
Thinly slice the English cucumber.
Arrange the cucumber slices evenly over half of the prepared bread slices.
Add additional fresh herbs over the cucumber layer, if desired.
Top each cucumber-covered bread slice with a remaining bread slice.
Using a sharp knife, remove the crusts from each sandwich, if not already removed.
Cut each sandwich into three equal pieces.
Serve immediately, or cover and refrigerate in an airtight container for up to 24 hours.