Heat oven to 425ºF. Combine 1 pkg. (10 oz.) frozen chopped spinach, thawed, squeezed dry; 4 oz. Crumbled Feta Cheese; 1/2 cup KRAFT Greek Vinaigrette Dressing. Spray 1 thawed phyllo sheet with cooking spray; top with 2 of the remaining thawed phyllo sheets, spraying each sheet with additional cooking spray before using as directed (You will need 3 sheets total per fillet). Place remaining phyllo sheets between sheets of plastic wrap; set aside until ready to use. Place 1 salmon fillet along one short side of phyllo stack; top with 1/4 of the spinach mixture. Fold over long sides of phyllo, then roll up, starting at fish-topped side. (Repeat with remaining phyllo sheets, fish and spinach mixture - Recipe makes 4 servings.) Place, seam sides down, on parchment-covered baking sheet; spray with cooking spray. Cut 3 diagonal slits in top of each wrap. Bake approx. 12-15 min. or until crusts are golden brown and fish flakes easily with fork. Meanwhile, mix 1/2 c. sour cream, 1/4 c. chopped cucumbers and 1 tbxp chopped fresh dill until blended Serve fish with sour cream mixture.