Wash the cucumbers and red bell pepper thoroughly under cold water.
Slice the cucumbers and red bell pepper into thin, uniform strips using a chef's knife or mandoline for consistent thickness; aim for slices about 2-3mm thick.
Place the sliced cucumbers and red bell peppers into a large mixing bowl.
Measure and pour the vinegar over the vegetables, then sprinkle with sea salt. Toss gently with tongs or two spoons until evenly coated and the vegetables begin to release some moisture.
Let the salad sit at room temperature for 5 minutes to allow the flavors to meld and the crunch to be preserved.
Serve immediately as a crisp, colorful side salad, or refrigerate for up to 30 minutes for a colder, even crunchier texture.