Slice cucumbers in half lengthwise. Scrape out seeds. Slice into thin rings. Combine with sliced bird's eye chili and shallot. Set aside.
Whisk dressing ingredients together. Pour over cucumber salad. Marinate for about 30 minutes - 3 hours before serving.
Notes
Add grated carrots and chopped, roasted peanuts for a little crunch.For a less spicy version, use about 1/4 red bell pepper, sliced, instead of a chili. I recommend marinating it for about two or three hours before serving it. If you marinate it for too long, it will get very vinegary. To save leftovers, discard the marinade.