Preheat oven to 325 degrees F. Line an 8x8x2-inch baking pan with foil-lined parchment pan lining paper, extending paper beyond the ends of the pan; set aside.
In a small skillet toast cashews over medium heat about 4 minutes or until golden brown and fragrant; transfer toasted nuts to a small bowl. Add agave nectar, brown sugar, peanut butter, and sesame seeds to hot skillet; cook and stir over medium heat until sugar is dissolved and completely combined.
In a large bowl whisk together egg whites and salt until frothy. Stir in peanut butter mixture. Add cereal and cashews; stir until cereal is well coated. Spoon mixture into the prepared pan; using the back of a large spoon press mixture firmly into pan. Bake for 35 to 40 minutes or until firm and golden brown. Let cool completely in pan on a wire rack. Using the edges of the pan lining paper, lift the uncut bars out of the pan. Cut into 15 bars.