Combine corn starch, flour, baking powder, garlic salt, onion powder, black pepper and cayenne pepper in a medium bowl. Add beer (or water) and egg; stir until mixture is smooth.
Heat 2 to 3 inches of oil in a deep pot over medium heat to 375°F.
Dip okra into batter, stirring batter occasionally. Fry a few pieces at a time, turning once, 2 to 3 minutes or until golden brown and crisp.
Drain on paper towels. Serve immediately.