In a mixing bowl, combine cream cheese, shredded cheddar cheese, garlic powder, and fresh chives. Mix thoroughly until well blended and creamy.

Season the mixture with salt and pepper to taste.

Take cucumber slices and use them as a base. Spread a generous layer of the cheese mixture over each slice.

For the avocado, scoop out some flesh and mix it with a pinch of salt and pepper. Optionally mash it for a creamier texture.

Place the mashed avocado on one half of the cucumber slices, creating a simple sandwich.

Top with additional chives for garnish if desired and serve immediately.