01 - Whisk together olive oil, soy sauce, lemon juice, garlic, oregano, paprika, black pepper, and salt in a large bowl until fully combined.
02 - Add beef cubes to the marinade, toss thoroughly to coat all surfaces, cover, and refrigerate for at least 1 hour (up to 6 hours for deeper flavor development).
03 - Preheat grill or grill pan to medium-high heat, approximately 400°F.
04 - Thread marinated beef cubes, bell pepper pieces, and red onion chunks alternately onto skewers, leaving slight space between items for even cooking.
05 - Grill kebabs for 10–15 minutes, turning every 3–4 minutes, until beef reaches desired doneness and vegetables show light charring.
06 - Remove skewers from grill and let rest for 5 minutes to allow juices to redistribute. Garnish with chopped fresh parsley and serve with lemon wedges.