Rinse the wood ear mushrooms and soak them in water for about 20 minutes until they rehydrate and soften. Roughly chop them once ready.
Trim the ends off the cucumber. Using the side of a cleaver or a rolling pin, gently smash the cucumber until it starts to crack and split.
Cut the smashed cucumber into bite-sized pieces. Sprinkle with salt and toss to coat evenly. Let it sit for 15 minutes to draw out excess moisture. Rinse the cucumber to remove the salt, then drain well.
In a mixing bowl, combine the wood ear mushrooms, cucumber, minced garlic, soy sauce, Chinese black vinegar, chilli oil, sugar, white sesame seeds, and a drizzle of sesame oil. Toss everything together until well mixed.
Chill the salad in the fridge for 30 minutes to let the flavours meld, or enjoy immediately if you prefer.
