Slice the cucumbers into 1/4-inch rounds—this thickness is crucial for achieving that perfect balance between crunch and pickle absorption. Slice the chili pepper into thin rings, removing seeds if you prefer less heat. Layer the cucumber slices and chili pepper into a clean glass jar, distributing them evenly as you go. I like to pack them fairly snugly so they stay submerged once the brine is added, but don't crush them.

In a separate bowl or measuring cup, whisk together the rice vinegar, lime juice, and granulated sugar until the sugar dissolves completely. Smash the garlic cloves with the side of your knife to release their aromatic oils—this creates a more intense, rounded flavor than mincing. Slice the scallions on a bias into thin pieces and roughly tear the mint sprigs by hand to bruise the leaves and release their oils. Add all of these aromatics plus the salt to your vinegar mixture and stir well to combine.

Pour the entire brine mixture over the cucumbers and chili peppers in the jar, making sure all the vegetables are fully submerged. Use a spoon or chopstick to gently press down any cucumber slices that try to float above the liquid. Sprinkle the toasted sesame seeds over the top for garnish and subtle nutty flavor, then close the jar tightly with its lid.

Place the sealed jar in the refrigerator and let it sit undisturbed for 24 hours. The cold temperature slows any fermentation and allows the flavors to gently infuse into the cucumbers. I always give the jar a gentle shake after about 12 hours if I remember—this helps redistribute the aromatics, though it's not strictly necessary. After 24 hours, your pickles are ready to enjoy and will stay crisp and flavorful in the fridge for up to 2 weeks.