beef, kabobs, grilling, peppers, onions, with yogurt cucumber sauce

Ingredients

• 10 garlic cloves
• 1/2 cup extra virgin olive oil
• 1/4 cup balsamic vinegar
• 2 tablespoons red wine vinegar
• 2 tablespoons fresh lemon juice
• 2 tablespoons chopped fresh mint
• 2 pounds top sirloin steaks, cut into 20 (1 1/2-inch) pieces
• 1 large red onion, quartered
• 2 medium green bell peppers, cut into 1 1/2-inch pieces
• 2 tablespoons kosher salt
• 1 tablespoon freshly ground black pepper
• 1 teaspoon ground allspice
• 1/4 teaspoon ground cinnamon
• Wooden or metal skewers
• 1 cup plain Greek yogurt
• 1 tablespoon minced garlic
• 1/2 cucumber, peeled, seeded, and finely grated
• 1 1/2 teaspoons fresh lemon juice
• 1/4 teaspoon kosher salt