1. Cook pasta according to package directions. Drain well, and set aside.
2. Whisk together lemon juice and next 4 ingredients. Gradually add oil in a slow, steady stream, whisking until blended. Cover and chill until ready to use.
3. Combine cooked pasta, shrimp, and next 4 ingredients in large bowl. Drizzle with vinaigrette, tossing to coat. Cover and chill 1 hour. Serve on lettuce-lined plate, if desired.