Grilled Red Onion and Cucumber Salad with Yogurt-Mint Dressing

Salad:

• 2 red onions, peeled and sliced 1/2-inch thick, crosswise
• Olive oil
• Salt and pepper
• 3 cucumbers, peeled, halved lengthwise and sliced 1/2-inch thick
• 3 tablespoons finely chopped fresh oregano
• 1/2 cup crumbled feta cheese

Yogurt-Mint Dressing:

• 1 cup plain yogurt, drained in fine sieve about 30 minutes
• 2 tablespoons tahini
• 1 tablespoon olive oil
• 2 tablespoons fresh lemon juice
• 2 cloves garlic, finely chopped
• 1/4 teaspoon cumin
• 1/4 cup mint chiffonade
• Salt and freshly ground pepper