Lay cucumbers on a board. Smash with the flat of a large knife or a rolling pin until they crack and split lengthways. Tear or chop into rough 3cm pieces.
Put in a colander, toss with sea salt flakes. Leave 10 minutes to drain.
Whisk together garlic, soy, vinegar, sesame oil, and sugar.
Squeeze excess water from the cucumbers, transfer to a bowl. Pour over dressing. Toss.
Spoon onto a shallow plate. Drizzle chilli crisp, scatter sesame seeds, coriander and spring onions. Serve immediately.