Mix ground beef, onion and salt. Shape mixture into 6 patties, each about 3/4 inch thick. Cook patties in a 10-inch skillet over medium-high heat, turning once, until brown. Cover and cook over low heat 10 minutes; drain.

Mix catsup, chili sauce, brown sugar and lemon juice. Pour over patties. Cover and simmer 15 minutes, spooning sauce onto patties occasionally. Place patties on buns; spoon sauce over patties. 6 sandwiches; 440 calories per sandwich.