Preheat oven to 400° F. Cut the avocados in half and remove the pits. Rub the insides of each half with fresh lemon juice to help them maintain their bright color. Set aside. In a medium mixing bowl, add chopped spinach, tomato, bacon, salt, pepper and 1 tablespoon mayonnaise. Stir to combine. Stuff the avocados with the filling, allowing the filling to mound at the top. In a small mixing bowl, add grated Parmesan cheese to seasoned Panko breadcrumbs and stir. Top the filling generously with the breadcrumb mixture. Place the avocados on a baking pan covered with foil and bake approximately 10-12 minutes, or until the breadcrumb topping has turned a golden brown. Mix remaining tablespoon of mayonnaise with Sriracha sauce in a small bowl and drizzle over each avocado half. Serve immediately.