For the lucky mushrooms, first cut the mozzarella balls flat at one end. Cut the cocktail tomatoes in half widthwise, using only the round top half.
Using a broken toothpick, place the tomato halves on top of the mozzarella balls. Use the mayonnaise to trace the toadstool dots.
For garnish, thinly slice a cucumber and cut into strips.
Arrange the lucky mushrooms on the cucumber strips and serve sprinkled with salt and pepper.