Rinse the rice in cold water until clear, then soak for 30 minutes. Drain.
Combine rice, water, bouillon, and turmeric in a small pan.
Bring to a boil, then simmer covered for 15 minutes, or until rice is tender and water is absorbed. Fluff with a fork and set aside.
Mix yogurt, mayo, minced garlic, lemon juice, salt, and pepper in a bowl. Refrigerate.
Heat oil in a large skillet over medium-high heat.
Sauté onion until translucent, then add garlic and cook for 30 seconds.
Add ground beef and cook until browned, breaking it apart.
Stir in shawarma spice, salt, and pepper. Cook for a few minutes. Remove from heat.
Place rice in a bowl. Top with beef, tomatoes, and cucumber. Drizzle with sauce and sprinkle parsley.