Place the cookies in a food processor and pulse until they're fine crumbs. It may be necessary to do this in batches, depending on the size of your food processor.
In a small mixing bowl, stir to combine the cookie crumbs and melted butter. Press the crumb mixture evenly into the bottom of a 9 x 13 dish. Place the dish in the refrigerator to chill while you prepare the filling layers.
In a large bowl, whisk to combine the orange gelatin mix and boiling water for 2 minutes, or until fully dissolved. Set aside.
In a meidum bowl, whisk the instant pudding mix and milk together for about 2 minutes, or until smooth and combined. Add the pudding mixture to the gelatin mixture and stir to combine. Set aside.
In a large mixing bowl, use an electric mixer to beat the cream cheese and confectioners sugar together until smooth. Fold in half of the Cool Whip, reserving the rest for later.
Spread the cream cheese mixture over the cookie crust in an even layer. Follow with an even layer of the orange jello/pudding mixture. Top with the remaining Cool Whip.
Cover and refrigerate for at least 4 hours (or overnight).
Top with mandarin orange segments before serving. If desired, and small mint leaves to the ends of the orange slices to make them look like little oranges.
Notes
Store covered in the refrigerator for up to 4 days.Graham cracker crumbs can be used instead of cookie crumbs if you don't have access to a food processor.