Use a spoon and scrape out the seeds from the cucumber, and discard them.
Dice the cucumber into small pieces or shred with the large holes of a box grater. Mix the cucumber pieces in a strainer with the salt, and let them stand for about 30 minutes, shaking and turning them a few times to encourage them to expel their water.
After they’ve drained, squeeze the cucumber pieces in a dishtowel to get out most of the excess liquid, and transfer them to a large bowl.
Mix the cucumbers with the garlic, yogurt, herbs, and olive oil, and taste, adding more salt if desired. Depending on the brand of yogurt, you might want to add a squirt of fresh lemon juice if you want it more tangy.
You can use any herbs that you like. I prefer heavy on the mint, with a good dose of dill in there. Some folks like flat leaf parsley as well (coming later this season!).
Tzatziki is actually better served the day after it’s made, so plan accordingly. It can be made up to three days in advance.