Trim ends from cucumbers and cut crosswise into 3/4-inch-thick rounds. Scoop a 1/2-inch-deep depression from one side of each round with a small melon-baller, forming little cups. Drain cucumbers, cup sides down, on a paper towel for approximately 15 minutes. Mix cream cheese, chopped dill, lemon zest, lemon juice, and black pepper together in a small bowl. Spoon 1/2 teaspoon cheese mixture into each cucumber cup. Top each cup with 1 salmon strip and 1 dill sprig.