Marinated Cucumber Salad with Creamy Dill Sauce

Name: Marinated Cucumber Salad with Creamy Dill Sauce
Cuisine: Mediterranean, European
Ingredients: 1 or 2 large English cucumbers; 2 tablespoons extra-virgin olive oil; 3 tablespoons apple cider vinegar; 1 tablespoon Greek yogurt (or mayonnaise); 1 clove garlic, finely minced or crushed; 1 tablespoon minced fresh dill, plus additional for garnish; 2 tablespoons red onion, sliced; Salt and freshly ground black pepper, to taste