Rinse the cucumber. Don't peel it, just chop off both ends and slice it in half lengthwise. Remove the soft watery center with a teaspoon until you reach the firmer cucumber flesh underneath.

Then grate the cucumber.

Put it on a large plate and sprinkle evenly with a pinch of salt. This will soften the cucumber flavor and extract the water in the cucumber. Then put it aside to marinate for 15 minutes. In the meantime finely chop the garlic and crush it finely under the blade of your knife until you get a puree. Also chop the mint up finely. Add both the chopped mint and garlic puree to a large bowl together with the unsweetened Greek yogurt.

Stir well and season with a little pepper and the lemon juice or vinegar. Put the bowl with the yogurt in the fridge for now until needed later. Then transfer the grated cucumber to a clean and dry kitchen towel and tighten the towel into a ball. Squeeze out as much of the cucumber juice as you can.

Then add the squeezed out grated cucumber to the bowl of yogurt and stir well. Check the seasoning and add more pepper, salt or lemon juice to taste if necessary. Scoop the Greek tzatziki yogurt dip in a large bowl and serve cold as a dipping sauce for the freshly grilled chicken souvlaki skewers.