1. Place the leg of lamb in a glass bowl and rub down with garlic.
2. Add lemon zest, lemon juice, rosemary sprigs and 4 tablespoons of olive oil and let it marinate in the fridge for 25 minutes.
3. Drizzle 4 tablespoons of olive oil over the tomato, sliced onion and green beans. Also, season with salt and pepper.
4. Remove the lamb from the fridge and season both sides with salt and pepper.
5. Place on a hot grill of 400-450 degrees Fahrenheit for 25-35 minutes. Flip the lamb after the first 15 minutes.
6. At the same time, add the seasoned vegetables onto the grill and cook.
7. Once done, chop up the tomato and onion and add to a bowl with the green beans. Add oregano leaves and adjust salt and pepper.
8. Slice the lamb thin.
9. Plate the lamb and green beans and serve as main course.