Bring a large pot of salted water to a boil. Cut the tops off bell peppers and remove the seeds. Cook bell peppers in boiling water for 5 minutes; drain. Sprinkle salt inside each bell pepper and set aside.

Place ground beef and onion in a large skillet over medium heat; cook and stir until beef is browned, about 5 minutes. Drain off excess fat and season with salt and pepper. Stir in tomatoes, 1/2 cup water, rice, and Worcestershire sauce; reduce heat to low, cover, and simmer until rice is tender, about 15 minutes. Remove from heat and stir in cheese.

Preheat the oven to 350 degrees F (175 degrees C).

Stuff each bell pepper with beef and rice mixture; arrange open-side up in a baking dish.

Combine tomato soup with just enough water in a medium bowl to make the soup a gravy consistency; pour over the bell peppers and cover with aluminum foil.

Bake in the preheated oven until heated through and cheese is melted and bubbly, about 25 to 30 minutes.