In a sieve set over a bowl, toss the diced cucumber and onions with 1 teaspoon salt. Let it drain at least 1 hour at room temperature, or cover and refrigerate up to 8 hours.
With flat-side of chef's knife, mash garlic with 1/2 teaspoon salt and make a paste. Add garlic paste to the yogurt mixture with olive oil, lemon juice, dill, and chive. Season with salt and pepper.
Pat the chopped cucumber dry with paper towels, and add to the yogurt mixture. Keep the mixture refrigerated until ready to use and serve it with fried skate chicken, burgers or as a dip for veggies.
You can make your own thick yogurt by letting it sit overnight in paper towel over a sieve.