Preheat oven to 250°F with racks in upper and lower thirds. Melt butter in a small saucepan over medium-low heat and whisk in sugar, soy, hoisin, sesame oil, garlic powder, ginger and cayenne. Remove from heat. Combine popcorn, rice cereal, chow mein noodles, Asian snack mix, cashews and wasabi peas in a very large bowl. Drizzle with butter mixture and toss well to coat. Spread evenly in 2 large (18- by 13-inch) rimmed sheet pans. Bake, stirring every 15 minutes, a total of 1 hour. Cool completely in pans on racks.