Place eggs in a saucepan and cover with cold water. Bring water to a boil; cover, remove from heat, and let eggs stand in hot water for 10 to 12 minutes. Remove from hot water, cool, peel, and chop.

Evenly divide lettuce, tomatoes, avocado, cucumbers, and eggs between 4 salad plates. Top with crab and shrimp.

Prepare the dressing by whisking together mayonnaise, chili sauce, relish, salt, and pepper. Spoon dressing over salad and garnish with parsley and lemon.