Slice onions very thin.

Slice cucumbers very thin.

Mix sliced onions and cucumbers with salt in a bowl.

Let the mixture stand for 2 hours to draw out moisture.

Drain the cucumber and onion mixture for 15 to 20 minutes to remove excess liquid.

In a separate bowl, combine sugar, white vinegar, and celery seed.

Pour the sugar-vinegar mixture over the drained cucumbers and onions.

Mix well to ensure all ingredients are coated.

Transfer the mixture into clean jars.

Refrigerate the jars.

The pickles are ready to eat the next day.

The pickles will keep for up to 6 months in the refrigerator.