01 - Combine olive oil, minced garlic, dried oregano, smoked paprika, ground cumin, lemon juice, salt, and pepper in a bowl. Add the sirloin steak and coat thoroughly. Let marinate for at least 15 minutes, or refrigerate for up to 2 hours for deeper flavor.
02 - Rinse basmati rice under cold water until water runs clear. Transfer to a saucepan with water, olive oil, and salt. Bring to a rolling boil, reduce heat to low, cover tightly, and simmer for 12-15 minutes until liquid is absorbed. Remove from heat, stir in lemon zest and chopped parsley, then fluff with a fork.
03 - Preheat grill or grill pan over medium-high heat. Remove steak from marinade and cook for 3-4 minutes per side for medium-rare doneness, adjusting time as needed for preferred doneness. Transfer to a cutting board and let rest for 5 minutes before slicing thinly against the grain.
04 - Whisk together Greek yogurt, lemon juice, olive oil, grated garlic, chopped fresh dill, salt, and pepper in a small bowl until smooth and well combined. Adjust seasoning to taste.
05 - Divide lemon herb rice among four serving bowls. Arrange sliced steak, halved cherry tomatoes, diced cucumber, thinly sliced red onion, kalamata olives, crumbled feta, and fresh parsley on top. Drizzle generously with yogurt sauce and serve immediately.