Preheat the broiler. Place the tomatoes on a baking sheet, season with salt and pepper and broil until the edges brown slightly, 5 to 10 minutes. Transfer the tomatoes to a plate.
Place the toasted bread on the baking sheet and spoon the beans evenly on top. Cover with the tomatoes and drizzle with the Worcestershire sauce, then sprinkle with the cheese and scallions. Broil until golden and bubbly, about 3 minutes.