1. Preheat oven to 350°.
2. To prepare crust, line an 8-inch square metal baking pan with foil that extends 2 inches beyond sides; coat foil with cooking spray. Weigh or lightly spoon 5.6 ounces flour into dry measuring cups; level with a knife. Combine 5.6 ounces flour, 1/3 cup powdered sugar, 1 teaspoon tea leaves from 1 tea bag (discard remaining tea in bag), and salt in a bowl; cut in butter with a pastry blender or two knives until mixture resembles coarse meal. Press into bottom of prepared pan. Bake at 350° for 19 minutes or until lightly browned.
3. To prepare filling, place juice in a medium microwave-safe bowl. Microwave at HIGH for 30 seconds. Add remaining 1 tea bag to juice; cover and steep 10 minutes. Squeeze juice from tea bag into bowl; discard tea bag. Combine granulated sugar, 2 tablespoons flour, and baking powder in a bowl. Add rind and eggs to juice; stir with a whisk until combined. Add sugar mixture to juice mixture; stir with a whisk until well combined.
4. Remove crust from oven; pour filling onto hot crust. Bake at 350° for 23 minutes or until set. Cool in pan on a wire rack for 30 minutes. Remove from pan by lifting foil. Remove foil; cut into 16 bars. Sprinkle bars with 1 tablespoon powdered sugar.