Cut the cucumbers lengthwise in half. Use a spoon to scoop out the seeds and some of the flesh from the center. Do the same with the rest of the cucumber halves.
In a medium bowl, combine the drained tuna, softened cream cheese, finely chopped chives, capers, salt, and black pepper. Use a fork to mash and mix everything together.
Transfer the tuna mixture to a piping cone or small piping bag. Cut off the tip of the bag.
Pipe the tuna mixture into each cucumber half.
Cut the cherry tomatoes into quarters and place three pieces on top of each cucumber canoe.
Top with fresh dill and a little black pepper. Serve right away.
