Prepare Citrus Dipping Sauce.
Melt butter in a large nonstick skillet over medium-high heat. Add mushrooms; cook 5 minutes or until tender. Remove from heat. Combine mushrooms, cabbage, and next 7 ingredients; stir well. Add egg white and crabmeat, stirring gently to combine.
Brush water around edges of each potsticker wrapper; place 1 tablespoon crab mixture in center of each wrapper. Fold wrapper over, forming a semi-circle. Fold overlapping pleats into dough on one side, pressing to seal. (The pleats enable the potstickers to stand upright.) Place on a baking sheet; cover and chill 2 hours.
Heat 2 teaspoons oil in a large nonstick skillet over medium-high heat. Carefully add half of potstickers, and cook 2 to 3 minutes until browned on bottom. Add 1/2 cup water to skillet, and cover quickly. (Skillet will hiss and steam rapidly.) Steam 3 to 4 minutes until thoroughly cooked. Drain skillet, and repeat steam-fry procedure with remaining potstickers. Serve immediately with Citrus Dipping Sauce.