Combine first 3 ingredients, stirring with a whisk; brush mixture evenly over both sides of each gyoza. Fit 1 gyoza into each of 30 miniature muffin cups, pressing the gyoza firmly into base of cups. Bake at 375° for 12 minutes or until lightly browned; cool in pans on a wire rack. Carefully remove cups from pans.
Combine celery and next 10 ingredients (though crabmeat) in a large bowl; toss gently. Spoon 1 1/2 tablespoons crab mixture into each gyoza cup. Garnish each cup with a cilantro leaf, if desired.
Make the crab filling up to one day ahead, and keep chilled.