Cut the boneless leg of lamb into uniform 1.5-inch cubes.

In a bowl, combine the olive oil, fresh lemon juice, minced garlic, chopped fresh rosemary, Kosher salt, and freshly ground black pepper to create the marinade.

Add the lamb cubes to the marinade, ensuring they are well coated. Cover and marinate in the refrigerator for at least 30 minutes, or up to 24 hours for deeper flavor.

While the lamb marinates, cut the green bell peppers into 1.5-inch squares, similar in size to the lamb pieces.

If using wooden skewers, soak them in water for at least 30 minutes to prevent burning on the grill.

Thread the marinated lamb chunks onto the skewers, alternating with the green bell pepper pieces. Leave a small gap between each piece for even cooking. Aim for 4-5 lamb chunks per skewer.

Preheat your grill to medium-high heat. Clean the grill grates thoroughly and oil them well to prevent sticking.

Place the assembled skewers on the hot grill. Cook for about 8-12 minutes total, turning every 2-3 minutes to achieve an even char on all sides. For medium-rare lamb, the internal temperature should reach 135°F (57°C) when measured with an instant-read meat thermometer.

Transfer the cooked skewers to a platter and tent loosely with foil. Let them rest for 5-10 minutes to allow the juices to redistribute.

Garnish generously with freshly chopped parsley and chives before serving hot.