Chop up your onion and green pepper.
Brown beef with onion and green pepper in large skillet. Drain excess fat and return to skillet.
Stir in salt, bouillon, dry mustard, rice and water. Bring to boil.
Reduce heat, cover and cook until liquid is absorbed, about 25 minutes.
Stir in tomato. Sprinkle cheese over top. Cover and remove from heat.