Halve the cucumbers lengthwise. Put the cucumbers on a cutting board cut-side down, then use the side of a chef's knife to gently but firmly press down and smash them so that they lightly crack but do not fall apart. Slice the smashed cucumbers into 1-inch pieces.
Put the cucumbers in a colander and toss them with 1/4 teaspoon salt. Place a bag of ice on top of them and let them drain for 15 to 30 minutes.
Stir the ponzu, lemon juice, coconut aminos, sambal, sesame oil, ginger, scallions and garlic together in a medium bowl. Add the cucumbers and cilantro and toss to combine.