Preheat the oven to 400°F (200°C). Heat the 1 tablespoon olive oil in a frying pan over low heat. Add the onion, and cook gently for about 5 minutes until soft.
Stir in the garlic, and cook for a few more seconds. Now stir in the lamb. Sprinkle with the allspice and cinnamon, and cook for a few minutes, stirring occasionally. Season with salt and pepper.
Lay the flat breads on a baking sheet, and drizzle with a little olive oil. Spoon on the lamb mixture, and bake for about 10 minutes until the lamb is heated through. Scatter the pine nuts and mint leaves over each, and top with a generous dollop of hummus. Serve immediately.
If you prefer the lamb minced, whiz in a blender or food processor until finely chopped.