Preheat oven to 400°.
Combine flaxmeal and water; stir to form a slurry.
Add pecan halves to the container of a medium-sized food processor. Pulse until the form a coarse meal; be careful not to make pecan butter. Add flour, sugar, and salt; pulse until combined. Add butter; pulse until mixture resembles coarse meal. Transfer mixture to a bowl; stir in flaxmeal.
Press mixture into the sides and bottom of rectangular tart pan with a removable bottom. Press firmly on mixture with the bottom of a measuring cup. Spread fig preserves evenly over crust. Place plums on top of preserves. Spoon a portion of fig preserves on top of plums, if desired.
Bake at 400° for 20-25 minutes or until crust is golden. Cool completely; remove tart pan sides before serving. Also delicious served cold.