01 - In a large bowl, whisk together olive oil, lemon juice, dried oregano, smoked paprika, minced garlic, salt, and black pepper.
02 - Add the beef cubes to the marinade, tossing to coat thoroughly. Cover and refrigerate for at least 15 minutes, or up to 2 hours for deeper flavor.
03 - Preheat a grill or grill pan to medium-high heat. If using wooden skewers, soak them in water for 20 minutes to prevent burning.
04 - Thread the marinated beef, bell pepper pieces, and red onion wedges alternately onto the skewers.
05 - Grill the kebabs for 10 to 12 minutes, turning occasionally, until the beef is cooked to desired doneness and vegetables are lightly charred.
06 - Transfer to a serving platter. Garnish with fresh parsley and serve with lemon wedges.