Preheat oven to 350°F. Line bottom and sides of a 13- x 9-inch pan with heavy-duty aluminum foil, allowing 2 to 3 inches to extend over sides; lightly grease foil with cooking spray.
Pulse flour, granulated sugar, and salt in a food processor until combined. Add butter cubes, and pulse until mixture is crumbly. Reserve 1 cup flour mixture. Press remaining flour mixture onto bottom of prepared pan.
Bake in preheated oven until lightly browned, 25 to 30 minutes. Spread cherry pie filling over crust in pan. Toss together reserved 1 cup flour mixture and pecans. Sprinkle pecan mixture evenly over filling.
Bake in preheated oven until golden brown, 40 to 45 minutes. Cool completely in pan on a wire rack, about 1 hour. Lift baked bars from pan, using foil sides as handles.
Stir together powdered sugar, 4 teaspoons milk, and almond extract. Add additional milk, if needed, to reach desired consistency. Drizzle over pecan mixture. Cut into 48 bars.