Step 1

Combine cucumbers and salt in a large, shallow bowl; cover and chill 1½ hours. Move cucumbers into a colander and rinse thoroughly under cold water. Drain well, and return cucumbers to bowl. Add onion to the bowl and toss with the cucumbers.

Step 2

Combine the granulated sugar, white vinegar, apple cider vinegar, brown sugar, mustard seeds, celery seeds and ground turmeric in a medium saucepan; bring to a simmer over medium heat, stirring until the sugar dissolves.

Step 3

Pour the hot vinegar mixture over cucumber mixture; let stand at room temperature 1 hour. Cover and refrigerate 24 hours. Store in an airtight container in refrigerator up to 1 month.