Pre-heat the oven to 375°F.
On a slotted broiler pan, bake the bacon until crisp, 15-20 minutes.
In a small saucepan, heat 1 tablespoon EVOO, one 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 sundried tomatoes, vinegar, brown sugar and Worcestershire sauce and bring to a boil. Lower the heat and simmer until thick, 7-8 minutes.
Season the tuna with the grill seasoning. In a large skillet, heat the remaining 1 tablespoon EVOO, one 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 four slices with lettuce, one tuna steak, two bacon strips and a pile of tomato jam. Cover with the remaining toasts.