Toast outside edges of buns in a sauté pan with a tablespoon of olive oil.
Mix shrimp with all other ingredients.
Put shrimp salad in toasted bun.
Whisk together the olive oil, lemon juice, salt and pepper for lemon dressing.
Toss baby arugula with lemon dressing, divide into eight small bowls and garnish each with two wedges of plum, two basil leaves and shaved parmesan.