In a medium bowl, combine the vegan cream cheese, matcha powder, lemon juice, and chopped dill (if using). Mix until smooth and well combined. Season with salt and pepper to taste.
Lay out the slices of whole grain bread on a clean surface. Spread a generous layer of the matcha cream cheese mixture on four of the slices.
Arrange the thinly sliced cucumbers evenly over the cream cheese layer. You can overlap them slightly for a beautiful presentation.
Top with the remaining slices of bread to create sandwiches. Gently press down to secure.
Using a sharp knife, cut the sandwiches into quarters or triangles for easy serving.
If desired, garnish with fresh dill or microgreens on top before serving.