In a bowl, whisk together the vinaigrette ingredients. Set aside. Halve the avocados. Remove the pit and cut the flesh into cubes. Drizzle with lemon juice to prevent browning. Set the avocado half-shells aside for service. In a bowl, gently toss the avocado cubes, mango, shrimp, and black olives. Pour the vinaigrette over the salad and toss gently.
To serve, spoon the salad into the hollowed-out shells. Garnish with fresh dill.