The pleating of these dumplings is a bit more advanced; if guests have trouble, they can make half-moons and skip the pleating. Make the chile oil up to 5 days ahead; store in the fridge, but bring to room temperature before serving.
Serves 6 (serving size: 3 dumplings)
1. Heat a small skillet over medium-high heat. Add whole chiles to pan; cook 1 to 2 minutes or until darkened and fragrant. Remove from pan; discard stems. Place chiles in a mini food processor; process until finely chopped (chiles should resemble crushed red pepper). Heat canola oil in pan 30 seconds over medium-high heat or until oil shimmers. Remove from heat; add chiles to hot oil. Let stand at room temperature 5 minutes. Stir in 1 teaspoon sugar, sesame oil, 2 teaspoons soy sauce, vinegar, and 1 garlic clove.
2. Add pork to food processor; pulse 6 times or until ground. Add remaining 1 teaspoon sugar, remaining 1 teaspoon soy sauce, remaining 1 garlic clove, 1/4 cup chives, ginger, white pepper, and egg; pulse 2 to 3 times to combine.
3. Working with 1 gyoza skin at a time (cover remaining skins to prevent drying), place skin on a work surface, starchy side up. Moisten edge of skin with water. Spoon about 2 rounded teaspoons pork mixture into center of skin. Fold wrapper in half, pressing well to seal edge. Lightly moisten one edge of wrapper; pleat edge, pressing to seal pleats. Place on a baking sheet lined with plastic wrap coated with cooking spray. Cover with a damp towel or paper towels to prevent drying. Repeat procedure with the remaining gyoza skins and filling.
4. Line each tier of a 2-tiered bamboo steamer with cabbage or lettuce leaves. Arrange 9 dumplings, 1 inch apart, over leaves in each basket. Stack tiers; cover with steamer lid. Add water to a skillet to a depth of 1 inch; bring to a boil. Place steamer in pan; steam dumplings 8 minutes or until done. Discard leaves. Spread 2 teaspoons chile oil over a platter; top evenly with dumplings. Drizzle remaining chile oil over dumplings; sprinkle with remaining 1/4 cup chives and sesame seeds.