In a large mixing bowl, combine softened cream cheese and mayonnaise, whisking until smooth and creamy. Add lemon zest, lemon juice, garlic powder, onion powder, dill, salt, and pepper, mixing thoroughly.

Lay out slices of bread on a clean surface and spread a generous layer of the herbed cream cheese mixture on each slice.

Thinly slice cucumbers into rounds, aiming for even thickness, and place them on a paper towel to absorb moisture.

Layer cucumber slices over half of the cream cheese spread slices, adding extra herbs if desired, then top with remaining slices of bread.

Cut each sandwich into three equal pieces and arrange on a serving platter. Enjoy immediately or cover and refrigerate for up to 24 hours.