Spiced Beef and Chicken Kabobs with Cucumber Yogurt

Name: Spiced Beef and Chicken Kabobs with Cucumber Yogurt
Ingredients: 1 cup plain low-fat Greek yogurt; 2 tablespoons chopped fresh mint; 1 tablespoon fresh lemon juice; 1 Persian cucumber, finely chopped; Kosher salt; 1/2 cup plain low-fat Greek yogurt; 1/4 cup finely chopped fresh cilantro; 1 teaspoon ground coriander; 1/2 teaspoon ground cumin; 1/2 teaspoon ground turmeric; 1/4 teaspoon ground allspice; 3 tablespoons olive oil; Kosher salt and freshly ground black pepper; 1 pound beef sirloin tip, cut into 3/4-inch pieces; 1 pound boneless, skinless chicken thighs, cut into 3/4-inch pieces; 12 mixed-color baby bell peppers (about 8 ounce); 1 red onion, cut into 1/2-inch pieces; Lemon wedges, for serving