Preheat the oven to 450 degrees and spray a large baking sheet with nonstick cooking spray.
In a medium bowl, toss the potatoes with the oil and half the salt, spread them on the baking sheet, and roast them for 25 minutes, tossing once, until they are nicely browned and crispy.
After flipping the potatoes, in a large nonstick skillet over medium heat, brown the beef. While it is cooking, season it with the rest of the salt and the allspice, cinnamon, cumin and paprika. Cook the beef until it is completely cooked through, about 10 minutes.
Warm the pita, if using, in the microwave for about 30 seconds until it is soft.
On small dinner plates, spread about 1/4 cup of the hummus, then top it with the meat and potatoes, pine nuts, cucumbers and pomegranate seeds (optional). You can scoop it with or stuff it in the pita, or eat it with a fork if you prefer.