Teriyaki Seitan Kebabs

Name: Teriyaki Seitan Kebabs
Ingredients: 1/2 cup low sodium soy sauce; 1/4 cup organic brown sugar; 1 tablespoon rice vinegar; 2 garlic cloves, (minced); 1 1/2 teaspoons freshly grated ginger; 16 ounces seitan, (cut into bite-sized pieces (about 1-inch)); 1 cup diced fresh pineapple ((about 1-inch pieces)); 1 small red bell pepper, (cut into 1-inch pieces); 1 small zucchini, (cut into 1-inch pieces); 1/2 medium red onion, (cut into 1-inch pieces); 2 teaspoons toasted sesame seeds; 2 tablespoons finely chopped fresh cilantro ((optional))