Preheat oven to 200°.
Combine the first 6 ingredients in a large bowl; set aside. Melt the butter in a small saucepan over medium heat. Add sugar and remaining ingredients, stirring with a whisk. Pour butter mixture over cereal mixture, tossing gently to coat. Spread the mixture onto a jelly roll pan coated with cooking spray. Bake at 200° for 45 minutes. Cool completely before serving.
Dried green peas coated with wasabi are available by the pound in some supermarkets, often in the bulk foods department. Don't worry if you can't find them; the mix is fine without them. Rice crackers are crunchy and airy, with the mild taste of rice. Look for them in the snack or Asian section of your grocery store.