Cream butter and sugar (in a stand mixer, or with a hand-held electric beater) on low speed until well-mixed. Add the egg in three doses, about 1 tbsp at a time; wait until each is fully incorporated, and scrape down the sides of the bowl before adding the next. Add salt, orange zest and optional orange oil. Sift flour, and add to bowl. Mix on low speed about 20 seconds, until a loose dough is formed. Wrap in plastic and pat into a flat disc. Refrigerate at least 1 hour.
Roll dough out to about 1/8" thick. Place dough into a 12" tart pan. Dock the bottom of the crust with a fork or rolling docker. Cover dough with parchment or foil and fill with beans or pie weights. Bake in preheated 350°F oven 15 minutes. Remove the weights and bake another 10 minutes until lightly browned. Cool to room temperature.
Meanwhile, beat together cream cheese, confectioner's sugar, grated ginger and salt. Beat with paddle attachment until fluffy and well mixed. Refrigerate until needed.
Combine cranberries, orange juice, sugar and salt in a medium saucepan. Bring to a boil. Let boil for 2 minutes, then cover tightly and allow to cool to room temperature.
Whip heavy cream and sugar until thick and holding fairly stiff peaks. Fold in orange juice and orange zest.
Spread cream cheese evenly over bottom of tart crust with an offset spatula, filling the corners. Pour the cranberries over the cheese and spread evenly. Refrigerate 4 hours or overnight. Serve with a dollop of whipped cream and a sprinkling of diced, candied ginger.