Step 1

In a bowl, mix together the shrimp, crabmeat, mayonnaise, chopped parsley, chopped radishes, chopped celery, shallots, lemon juice, cayenne, 1/2 teaspoon salt and a few grinds of pepper.

Step 2

Halve and seed the avocados. Use a spoon to scoop out most of the flesh, leaving 1/4 inch behind. Chop the avocado flesh and gently mix it into the seafood salad. Add salt and pepper to taste. Spoon the seafood salad into the avocado halves.

Step 3

Toss the arugula with the sliced celery, sliced radishes, parsley leaves, olive oil and a pinch of salt. Divide among 8 plates; nestle the avocado halves on top. Serve with lemon wedges on the side.