Wash the cucumber and cut it in half, length-wise. Scoop out the seeds from the cucumber and discard.
Grate the cucumber on a fine grater and place it into a mesh strainer. Salt the cucumber with some salt, mix it, and let it sit and drain off the excess moisture for about 10 minutes.
Combine all of the ingredients in the mixing bowl, gently squeeze the cucumber, and add it to the bowl. Mix well.
Serve right away of transfer into an air-tight container and refrigerate.
Store the Tzatziki sauce in the refrigerator, in an air-tight container, for 3-4 days.