Slice cucumbers on the bias about ¼-inch thick. Lay cucumbers on paper towels and cover with paper towels. Set aside.
Place tomatoes, onion, parsley, olives, and 3 tablespoons of feta in a medium bowl. Add Greek dressing and toss together.
Spread about ¼ teaspoon of hummus onto top of a cucumber slice. Top with a ½ -1 tablespoons of the tomato mixture. Repeat with the rest of the cucumber slices. Sprinkle last tablespoon of feta over the top of all the nachos. Serve immediately.