1. To prepare sauce, combine the 1st 5 ingredients.

2. To prepare dumplings, heat oil in a medium nonstick skillet over medium-high heat. Add leek and I tablespoon ginger, saute 3 minutes. Remove from heat. Combine leek mixture, mirin, salt, black pepper and shrimp, stirring well.

3. Working with 1 wonton wrapper at a time (cover remaining wrappers with a damp towel to prevent drying), spoon about.1 tablespoon shrimp mixture into center of each wrapper. Moisten edges of wrapper with water, bring 2 opposite corners to center, pinching points to seal. Bring remaining 2 corners to center, pinching points to seal. Pinch 4 edges together to seal.

4. Add water to a wok or large skillet to a depth of 1 inch, bring to a boil. Line a bamboo steamer with leafy lettuce. Place about 15 dumplings on top of lettuce. Cover with steamer lid. Place steamer in pan, steam dumplings 12 minutes. Remove dumplings from steamer, cover and keep warm. Repeat procedure with the remaining dumplings. Serve with sauce.