Pre-heat the oven to 375°F. Bake the bacon on a broiler pan until crisp, about 15 minutes.
While the bacon is working, arrange the bread on a baking sheet and lightly toast in the oven, about 5 minutes.
In a large skillet, heat a drizzle of EVOO over medium-high heat. Add the chicken and cook, turning once, until golden, 4-6 minutes; season with salt and pepper. Stir in the butter and hot sauce.
In a small bowl, mash the avocado with the garlic and lemon juice; season with salt. In another small bowl, mash the blue cheese with the crème fraîche. Spread the avocado mash on 4 toasts and top each with a lettuce leaf, a chicken breast half, 2 tomato slices, an onion slice and 2 crisscrossed bacon strips. Spread the blue cheese dressing on the remaining toasts and set on top. Slice the sammies into 4 triangles each.