Spread the hummus in a smooth layer in the bottom of an 8x8-inch square baking dish, a shallow pie dish, or similar serving dish. Dollop the Greek yogurt by small spoonfuls over the top, then gently spread to create a new layer. Scatter the tomato, cucumber, feta, and olives over the top. Sprinkle with fresh parsley. Refrigerate until ready to serve, then dip with pita chips, crackers, and sliced veggies as desired.