Vegetable Gyoza With Orange Ponzu Sauce

Ingredients

• 2 cups finely chopped cabbage
• 4 cups finely chopped shiitake mushrooms, stemmed
• 1/2 yellow onion, chopped finely
• 3 scallions, chopped finely
• 4 cloves garlic, minced
• 2 teaspoons minced ginger, or 1 teaspoon ginger powder
• 1 tablespoon roasted sesame seeds
• 1/4 cup reduced-sodium soy sauce
• 2 tablespoons roasted sesame oil
• 1 tablespoon sugar
• 1 cup panko breadcrumbs
• all-purpose flour, for dusting
• 1 package (about 40-50) gyoza or wonton wrappers
• 1 tablespoon canola oil, plus more as needed
• 3 tablespoons rice-wine vinegar
• 1 teaspoon freshly grated orange zest
• 1 teaspoon sugar (optional)