Combine hoisin sauce, all-purpose soy sauce, dark soy sauce, rice wine vinegar, brown sugar, and Chinese five-spice in a small bowl. Stir until the sugar dissolves and the mixture is smooth.

Heat olive oil in a frying pan or wok over high heat until shimmering.

Add minced beef to the hot oil, cooking undisturbed for 5-6 minutes until browned, then break apart and continue cooking for another 1-2 minutes.

Stir in minced garlic and grated ginger, cooking for 30 seconds until fragrant.

Pour the sauce mixture over the beef, reduce heat to medium, and simmer for 1-2 minutes while stirring.

Mix cornflour with water to create a slurry, then pour into the simmering beef while stirring continuously until the sauce thickens.

Prepare cucumber ribbons by peeling thin slices and salting lightly to draw out moisture.