Toast the cumin and sesame seeds in a large dry frying pan (skillet) for 30 seconds then set aside.
Heat 2 tbsp of the oil in the pan and gently fry the onion and garlic until soft but not brown.
Place the lamb in a large bowl and add the cooked onion and garlic, the chopped mint and the egg. Reserve a few of the toasted seeds for the garnish and add the rest to the meat mixture. Season with salt and pepper and mix well with your hands then shape into 8 patties.
Wipe the pan clean with kitchen paper then heat the remaining oil and fry the meat patties for 3-4 minutes on each side or until cooked through.
Serve the burgers in the pita breads with a spoon of hummus in each garnished with the mint leaves and the reserved seeds.