Toss cucumbers, onion, and salt in colander set over a bowl. Let stand for 1 hour. In a pot bring vinegar, sugar, mustard seeds. celery seeds, and tumeric to a boil. Reduce heat and add cucumbers. Simmer for about 5 minutes or until cucumbers are a darker green color but still crisp. Remove cucum- bers from heat and place into a stainless bowl set over a bowl of ice water to cool. Refrigerate when cool enough. This may take about an hour. When cold, package into ball jars. These will keep refrigerated for up to about 3 weeks.