Combine water and bulgur in a bowl; cover and let stand 20 minutes. Drain well, and press excess liquid out of bulgur.
Heat walnuts in a large skillet over medium heat until walnuts are hot. Add soy sauce; cook 20 seconds or until liquid evaporates, stirring constantly. Remove from pan. Wipe pan with a paper towel.
Heat pan over medium-high heat. Coat the pan with cooking spray. Add onion; sauté 5 minutes or until golden. Add garlic; sauté 30 seconds. Add 2 cups chopped spinach; cook 30 seconds. Add bulgur, walnuts, and salt; stir well.
Combine juice and egg yolks in a large bowl. Add bulgur mixture. Spoon flour into a dry measuring cup; level with a knife. Add flour to bulgur mixture; stir well. Beat egg whites with a mixer at high speed until soft peaks form. Fold whites into bulgur mixture.
Heat oil in a nonstick griddle or large nonstick skillet over medium heat. Pour 1/2 cup batter per pancake onto hot pan, spreading each to a 5-inch diameter. Cook 5 minutes or until bottoms are browned. Carefully turn pancakes over; cook for 4 minutes or until bottoms are golden. Transfer to plate; keep warm.
Heat pan over medium-high heat. Add 2 cups spinach; cook 2 minutes or until spinach wilts, stirring constantly. Serve with pancakes. Garnish with rind strips, if desired.