Spray grates of grill with non-stick cooking spray and set heat to high.
While grill is heating, prepare the gremolata by combining the parsley, lemon zest, garlic and preserved lemon (if using) in a small bowl. Season with salt and black pepper, to taste, and set aside.
¼ cup fresh parsley leaves, 1-2 teaspoons organic lemon zest, 1 large clove garlic, 1-2 teaspoons preserved lemon, salt and pepper
Brush tuna steaks with olive oil and sprinkle with Italian seasoning salt and pepper, to taste.
4 6-ounce sushi-grade tuna steaks, 2 tablespoons extra virgin olive oil, Italian seasoning, salt and pepper
Place tuna steaks and lemon halves over direct heat. Cook tuna for 2 minutes per side for rare. Increase time slightly for medium, but do not overcook.
2 large lemons
Remove tuna and grilled lemon halves from heat and serve immediately topped with some gremolata.