For crust, in a food processor combine oats, 3 Tbsp. of the flaxseed meal, and the tahini. Cover and pulse until mixed.
With processor running, slowly add 2 to 4 Tbsp. milk until mixture starts to cling together and is slightly moistened.
Press onto the bottom and up the sides of 9-inch pie pan.
For filling, combine the remaining 1 Tbsp. flaxseed meal with ¼ cup water; let stand 5 minutes.
Add to food processor with pumpkin, ¾ cup milk, the dates, date syrup, arrowroot, pumpkin pie spice, vanilla, and salt. Cover and process until smooth.
Spread filling into crust.
Bake 50 to 55 minutes or until filling is set. Cool on a wire rack 30 minutes. Chill 2 to 8 hours.