Use a food processor with pulse until the nuts are finely chopped. Transfer nuts to a small dry skillet and cook for 5-6 minutes until lightly browned. Remove from pan and set aside. Use the food processor to mince onion, garlic, peppers and cilantro. Drain any excess liquid. Add veggies to nuts, along with spices and the ground lamb. Mix thoroughly and form into patties about 2 inches in diameter and 1/2 inch thick. Preheat the grill to medium high heat, or a skillet to medium heat. Cook covered until browned on each side, about 4 minutes per side or until cooked through. Garnish with fresh mint leaves and serve with pita bread, tzatziki and hummus.