Wash the cucumbers; cut off the end pieces.
Set the cucumbers in front of you horizontally. Cut them into three equal parts.
Place three parts of the cucumbers into a large freezer bag. Seal the bag, releasing any extra air, and smack the cucumbers firmly with a rolling pin or a meat mallet. The cucumbers will flatten and split into 3-4 spears. Repeat this with all cucumbers.
Discard any of the seeds or mushy bits from the middle of the cucumber.
With your hands, break the cucumber spears into bite-sized chunks, then place them into a colander. Season them with salt and then, using your hands, toss to coat. Let them stand for 15 minutes.
In the meantime, whisk the vinegar and grated garlic together in a small mixing bowl. Let it stand for 5 minutes.
After 5 minutes, add soy sauce, sesame oil, and sugar in with the vinegar and garlic, then whisk until the sugar has fully dissolved.
Pop the cucumbers into a large serving bowl; pour the dressing on top.
Toss the cucumbers enough to coat them in the dressing and then drizzle 1-2 TBSP of the hot chili oil over them. Garnish with toasted sesame seeds and sliced scallions.
