Using a very sharp knife, or a mandoline set on the thickest setting, carefully slice your cucumbers into 1/4-inch slices.
Sprinkle each slice with a tiny pinch of salt, to help it bend when creating your trees.
Meanwhile, using a mini star-shaped cutter, cut stars from the cheese slices.
Slice your cherry tomatoes in half to create the bottom of the trees.
Pat your cucumber slices dry with a paper towel before assembling your trees.