Slice each avocado crosswise thinly. Remove the skin and seed from each sliced avocado.
Make batter. In a bowl, mix together onion powder, garlic powder, garlic salt, rice flour, cornstarch and baking powder. Then add water and olive oil to the bowl and mix to combine. Add black pepper to taste.
Heat enough canola oil to fly avocado slices in a fry pan over medium heat.
Put enough all-purpose flour to coat avocado slices on a plate. Dredge avocado slices in flour then dip in the batter.
When the oil gets hot, put avocado slices in the fry pan and fry until both sides are golden brown and crisp. Drain on paper towels.