Preheat oven to 350°F. Process graham crackers, ginger, and salt in a food processor until finely chopped. Add butter, and process until combined. Press mixture on bottom and 1 to 1 1/2 inches up the sides of a lightly greased 9-inch springform pan. Bake in preheated oven until lightly golden, about 12 minutes. Cool completely, about 30 minutes. Lower oven temperature to 325°F.
Beat cream cheese and sugar with an electric mixer on medium until smooth, about 4 minutes, stopping to scrape down sides of bowl as necessary. Add eggs, 1 at a time, beating just until incorporated. Add zest, juice, syrup, and vanilla, and beat just until combined. Pour into prepared crust.
Bake in preheated oven until center is almost set, 1 hour to 1 hour and 10 minutes. Cool completely in pan on a wire rack, about 4 hours. Cover and transfer to refrigerator; chill 8 to 24 hours. Top with whipped cream and Candied Grapefruit Peel.