Mix cream cheese, horseradish and green food color in medium bowl until well blended and smooth. Chop two green onions and stir into mixture. Reserve 1 tablespoon cheese mixture.
Spread 1/4 cup cheese mixture on a tortilla. Top with several slices of corned beef. Place 1 green onion top at edge of tortilla. Starting at this edge, roll tortilla up tightly. Seal opposite edge of roll with reserved cheese mixture. Repeat with remaining tortillas and ingredients. Wrap each tortilla roll individually in plastic wrap.
Refrigerate at least 1 hour or until ready to serve. Unwrap and cut tortilla rolls into 1-inch slices to serve.