Place the dried wakame in a bowl of warm water for 10 minutes until it expands and becomes tender, then drain and squeeze out excess moisture.
Bring a pot of water to a boil with a pinch of salt and cook the shrimp for 2-3 minutes until pink and opaque, then immediately transfer to an ice bath to chill.
In a small glass jar, whisk together the toasted sesame oil, tamari, rice vinegar, and freshly grated ginger until the dressing is emulsified.
Thinly slice the cucumber into half-moons and dice the avocado into bite-sized pieces.
In a large mixing bowl, combine the rehydrated seaweed, chilled shrimp, and cucumber slices.
Pour the dressing over the salad and toss gently to ensure every ingredient is coated in the savory sauce.
Transfer to a serving bowl and garnish with the toasted sesame seeds, sea salt, black pepper, and avocado.