Place Rice Chex and Corn Chex in a very large mixing bowl.
In a separate small bowl, whisk together the crushed strawberry powder and powdered sugar until uniform.
Melt the white chocolate wafers in a microwave-safe bowl in 30-second intervals, stirring after each interval until the chocolate is smooth and fully melted.
Pour the melted white chocolate over the cereal and gently fold with a large spatula until the cereal is thoroughly and evenly coated.
Immediately sprinkle the strawberry-sugar mixture over the cereal and toss gently until the powder adheres to the chocolate coating.
Spread the mixture out onto a large parchment-lined baking sheet in an even layer.
Gently press the whole freeze-dried strawberry slices into the mix while the chocolate is still tacky.
Allow the mixture to cool and harden completely at room temperature for approximately 30 minutes before breaking into clusters.