Preheat oven to 350°F. Blend ingredients in processor until graham crackers are finely ground. Add the vegetable oil; process until moist crumbs form. If it seems to dry, you could add a little water (or milk) a tablespoon at a time until you reach the right consistency. Press crumb mixture onto bottom and sides of pie pan. Press firmly to ensure the crust is even. Transfer to the freezer for 30 minutes.
In a small skillet on medium-low heat, simmer the blueberries with the sugar and Limoncello (or orange juice) for about 5 minutes. Add the blueberries to a blender and give it a whirl.
Whip cream until stiff peaks are just about to form. Beat in the sugar until peaks form. Take care not to over-beat, or you'll be left with butter.
On low speed, whip in pureed blueberries and the Greek yogurt until combined.
Stop the mixer and fold in the mixture, scraping the sides of bowl with a spatula until fully combined.
Spoon the blueberry filling into the graham cracker crust.
Decorate with blueberries.
Transfer the pie to the freezer and freeze until solid enough to slice, at least 2 hours or up to overnight. To make serving easier, let the pie sit out for 10 minutes at room temperature before slicing.