If using raw shrimp, bring a large pot of salted water to a boil. Add shrimp and cook for 2-3 minutes until pink and opaque. Transfer to an ice bath to stop cooking. Once cooled, peel, devein, and refrigerate until thoroughly chilled, at least 30 minutes.
Prepare the Louie dressing by combining mayonnaise, ketchup or chili sauce, pickle relish, lemon juice, Worcestershire sauce, hot sauce, minced garlic, and green onion in a medium bowl. Whisk until smooth and season with salt and pepper to taste. Refrigerate until ready to use.
Wash and dry the lettuce, then chop into bite-sized pieces. Transfer to a large salad bowl or arrange on a serving platter as the base.
Dice the tomatoes, cucumber, and red onion into uniform ΒΌ-inch pieces.
Slice the hard-boiled eggs into quarters or eighths, according to preference.
Just before serving, dice the avocado and add it to the salad to prevent browning.
Arrange the chilled shrimp, sliced eggs, diced tomatoes, cucumber, avocado, and red onion atop the lettuce in sections for visual appeal.
Sprinkle capers evenly across the salad.
Drizzle with prepared Louie dressing just before serving, or serve the dressing on the side.
Season with fresh cracked black pepper and a pinch of sea salt to taste.
Garnish with fresh chopped chives if using and serve immediately with lemon wedges on the side.
