Mix first 4 ingredients in small bowl. Set dipping sauce aside. Heat oil in medium skillet over medium-high heat. Add ginger; saute until fragrant, about 10 seconds. Add shrimp and cilantro; saute until shrimp are just cooked through, about 1 minute. Remove from heat. Season with salt and pepper. Pour hot water into large bowl. Using tongs, dip 1 spring-roll sheet in water 5 seconds. Remove from water; place on wet towel. Let stand 30 seconds (spring-roll sheet should be soft and pliable; if still stiff, sprinkle with more water). Place half of lettuce leaf across top third of spring-roll sheet. Arrange 4 shrimp halves on lettuce. Top with 1 tablespoon each of green onions and cucumber. Sprinkle 1/2 teaspoon mint over filling. Fold sides of spring-roll sheet over ends of filling. Starting at filled side, roll into cylinder. Place on plate. Repeat with remaining spring-roll sheets, lettuce, shrimp, green onions, cucumber and mint. Serve with sauce.