Instructions:1. In a medium bowl, stir vinegar, sugar, salt, and pepper until sugar and salt are dissolved.
2. Quarter cucumber lengthwise.
3. Remove seeds.
4. Cut quarters crossswise into 1/8-inch thick slices.
5. Add cucumber, onion, cilantro and chili to vinegar dressing; toss until combined.
6. Cover and marinate in the refrigerator for 3 hours, stirring occasionally.