Sprinkle gelatin over cold water and set aside to soften for 5 minutes.
Simmer pineapple juice in a saucepan over low heat until it is reduced to 1/2 cup. Cool. Beat egg yolks into pineapple juice. Stir in gelatin and 1/2 cup sugar. Place pineapple juice mixture in the top of a double boiler. Cook, stirring often, until gelatin is melted and mixture has thickened slightly, about 10 minutes. Remove from heat. Stir in salt and orange peel. Chill until mixture is room temperature, but not set, about 45 minutes.
Beat egg whites until frothy, then gradually add 1/4 cup sugar while continuing to beat. Beat until stiff peaks form. Fold in whipped cream. Fold egg white mixture into pineapple mixture, and spoon filling into cool pie shell. Chill several hours or overnight.
Garnish with 6 pineapple "flowers" made by arranging 5 pineapple tidbits around a maraschino cherry center. Serve.