Step 1In a bowl, combine the tomatoes, mint, parsley, capers, Aleppo pepper and lemon juice. Drizzle over about ¼ cup olive oil, and toss to combine. Taste and season with salt and pepper as desired. Cover and set aside.
Step 2Prepare the grill, making sure the cooking surface is very hot. Meanwhile, pat the fish dry using paper towels. Brush the steaks with olive oil and sprinkle with salt and pepper to taste.
Step 3Oil the grill, then add the steaks. Cook until the fish is opaque on the bottom and releases easily from the grate, 2 to 3 minutes. Flip the steaks over and cook on the other side. (A thin steak should take about 5 minutes.) Remove from heat. When the tuna is cool enough to handle, about five minutes, crumble over the tomato mixture and toss to combine.
Step 4Oil the grill. Add the bread slices and toast to your preferred state of char, then rub garlic cloves all over one side. Place the bread on a platter or plates and drizzle with olive oil. (I also like to salt the bread.) Halve the slices if they’re large. Divide the topping among the slices, drizzle with oil and serve immediately.