Preheat the oven to 375°. On a slotted broiler pan, bake the bacon until crisp, 15 to 20 minutes.
In a small saucepan, heat 1 tablespoon EVOO, 1 turn of the pan, over medium-high heat. Add the onion and garlic and cook until softened, 7 minutes; season with salt and pepper. Stir in 1/2 cup water, the sun-dried tomatoes, vinegar, brown sugar and Worcestershire sauce and bring to a boil. Lower the heat and simmer until thick, 7 to 8 minutes.
Season the tuna with the grill seasoning. In a large skillet, heat the remaining 1 tablespoon EVOO, 1 turn of the pan, over medium heat. Add the tuna steaks and cook for about 2 minutes on each side for medium-rare.
Toast the bread and drizzle with EVOO. Top 4 slices with lettuce, 1 tuna steak, 2 bacon strips and a pile of tomato jam. Cover with the remaining toasts.