Step 1

Heat a dry skillet over medium heat. Add red chile peppers; cook and stir until fragrant, about 5 minutes. Let cool and transfer to a spice grinder; pulse until coarsely ground.

Step 2

Mix ground chile peppers, soy sauce, spring onion, sesame oil, hot chile oil, brown sugar, garlic, black vinegar, and sesame seeds together in a bowl to make dressing.

Step 3

Place cucumbers on a serving plate. Pour dressing on top and toss well. Let sit before serving, about 3 minutes.