Combine rice flour, salt, and pepper in a shallow bowl. Place beaten egg in a separate shallow bowl.
Place rice puffs in a Ziploc bag. Using a mallet crush rice puffs until fine. Pour into a shallow bowl.
Brush a baking tray with some vegetable oil. Preheat oven to 400°F (200°C).
Slice avocado lengthwise around the seed. Twist and rotate the two halves apart. Strike the pit with the bottom edge of a knife to grab it. Rotate to loosen and release the pit from the fruit. Scoop out flesh with a large spoon and cut each half into 3 slices lengthwise. Repeat with the other avocado to yield 12 slices altogether.
Take a piece of avocado and dredge it in the flour mixture. Dip it in egg wash and coat it with crushed rice puffs. Place on baking tray with the pit side facing up. Repeat with the rest of the avocado slices.
Bake for 20 to 25 minutes or until golden brown. Remove and serve immediately.