To prepare shrimp, combine the first 7 ingredients in a large saucepan; bring to a boil. Reduce heat, and simmer 10 minutes. Strain cider mixture through a sieve into a large bowl; discard solids. Return cider mixture to pan; bring to a boil. Stir in shrimp; reduce heat, and simmer 5 minutes. Remove pan from heat. Let stand 30 minutes. Remove shrimp from cider mixture, and discard cider mixture. Chop shrimp; chill.
To prepare dressing, combine 1/2 cup cider and the next 4 ingredients (through horseradish) in a medium bowl, stirring with a whisk.
To prepare salad, place lettuce and remaining ingredients in a large bowl. Drizzle 1/2 cup dressing over lettuce mixture; toss gently to coat. Add shrimp to remaining dressing; toss to coat. Arrange shrimp on top of salad.