Lentil Piyaz (Marinated Turkish Salad)

Ingredients

• 2 cups (500 mL) red onion, halved and sliced thinly
• 2 Tbsp (30 mL) garlic, minced
• ½ cup (125 mL) white wine vinegar
• 1 quart (1 L) whole red lentils, cooked and drained
• 1 quart (1 L) Roma tomatoes, cut into thin lengthwise wedges
• ½ cup (125 mL) flat leaf parsley, roughly chopped
• 1 Tbsp (15 mL) sumac
• ¼ cup (60 mL) extra virgin olive oil