Add the poppy seeds, sesame seeds, dried minced garlic, dried minced onion, crushed caraway seeds, and coarse salt to a small bowl.
Stir thoroughly until the homemade everything bagel seasoning is evenly combined. Set aside.
Wash and thoroughly dry the cucumber.
Using a vegetable peeler or sharp knife, remove alternating strips of cucumber skin lengthwise to create a decorative striped appearance.
Slice the cucumber crosswise into approximately ¼-inch-thick rounds.
Arrange the cucumber slices in a single layer on a serving platter.
If the cucumber slices have excessive surface moisture, gently blot them with a clean paper towel.
Add the softened cream cheese, butter, Greek yogurt or sour cream, garlic powder, and salt to a medium mixing bowl.
Beat until the mixture is completely smooth, creamy, and well combined.
Fit a piping bag with a star-shaped piping tip and fill it with the cream cheese mixture.
Pipe a decorative swirl of cream cheese mixture onto the center of each cucumber round.
Sprinkle the homemade everything bagel seasoning generously over each Everything Bagel Cucumber Bite.
Arrange on a serving platter and refrigerate briefly if necessary.
Serve chilled or cool for the freshest flavor and crispest texture