In a large bowl, combine the ground meat, minced garlic, chopped red onion, parsley, dried oregano, salt, and black pepper, and mix gently until evenly combined.
Shape the mixture into evenly sized meatballs.
Heat olive oil in a pan over medium heat and cook the meatballs until fully cooked and lightly browned on all sides.
While the meatballs are cooking, prepare the vegetables by chopping the lettuce, cucumber, tomatoes, and red onion.
In a small bowl, mix the Greek yogurt, lemon juice, olive oil, garlic, salt, and black pepper until smooth.
Assemble the bowl by adding the lettuce, vegetables, cooked meatballs, and drizzle with the yogurt sauce before serving.