Wrap each cucumber in cling film to minimise splattering.
Place on a work surface and pound with a flat object (could use a meat tenderiser or rolling pin) until the cucumbers crack and are slightly flattened. Remove from the cling film.
Slice into 1- to 1 1/2 -inch wide slices.
Transfer to a strainer set over a bowl.
Sprinkle cucumber with sugar and salt.
Mix the cucumbers and salt until combined.
Refrigerate bowl and strainer for 30 to 60 minutes so cucumber pieces can drain into the bowl.
Place garlic, seasoned rice vinegar, soy sauce, sesame oil, and ginger in a large bowl.
Whisk together thoroughly.
Transfer drained cucumbers into the bowl with dressing.
Toss to coat.
Place cucumbers in a serving bowl and sprinkle with sesame seeds.