Lay each cucumber on your cutting board. Use the flat side of your chef's knife to firmly smash the cucumber in several spots along its length. You will hear it crack and split. Then cut the smashed cucumber crosswise into rough 1-inch chunks. The jagged edges are what you want here because they grab the brine.

Toss the cucumber pieces in a colander with the kosher salt. Let them sit over the sink or a bowl for ten minutes. This pulls out excess water so the brine is not diluted. After ten minutes, shake the colander and pat the cucumbers gently dry with a clean towel.

While the cucumbers drain, whisk together the rice vinegar, soy sauce, sesame oil, sugar, grated ginger, and minced garlic in a large mixing bowl. Stir until the sugar fully dissolves, about thirty seconds.

Add the drained cucumbers to the bowl and toss well to coat every piece. Transfer everything to a glass jar or airtight container, making sure the cucumbers are mostly submerged in the brine. Refrigerate for at least two hours. Overnight gives a deeper, more developed flavor.

Toast the sesame seeds just before serving. Add them to a small dry skillet over medium heat and shake the pan for about two minutes until they turn golden and smell nutty. Pull them off the heat right away so they do not burn.

Spoon the pickled cucumbers into a serving bowl with some of the brine. Scatter the toasted sesame seeds and sliced green onions over the top. Taste and add a tiny splash more soy sauce or vinegar if you want a sharper edge. Serve cold.