Brown beef in skillet; drain off fat. Add luncheon meat, tomato paste, onion, orégano, sage, salt, pepper and 1 c. grated cheese; mix thoroughly. Cool and refrigerate until needed.
Split hamburger buns. Place ¼ c. meat mixture on bun half. Spread to cover bun. Sprinkle with 1 tblsp. remaining grated cheese and about ½ tsp. dried parsley. Repeat with remaining bun