Place the cucumbers and onions together in a large mixing bowl,
Add the salt.
Mix well.
Let stand for 2 hours at room temperature.
Rinse the cucumbers and onion in cool water.
Drain.
Place them in the freezer containers.
Mix the vinegar and sugar together until the sugar is completely dissolved.
Pour the mixture over the cucumbers and onions.
Freeze for at least 3 weeks before eating.
When ready to eat thaw in the refrigerator overnight or run under cold water if you want to thaw faster.