In a bowl, add and whisk together the flour, salt, black pepper, ground ginger, onion granules, and garlic granules. Pour in the water and whisk to a smooth batter. In another bowl, add and whisk the panko breadcrumbs and crushed chilli.
Take 1 prawn, dip it in the batter until fully coated then dip it into the breadcrumbs ensuring it is well coated and place on a plate or baking tray. Repeat the process with all the prawns until they are all used up. Allow the prawns to rest at room temperature for 10 minutes.
While they are resting, place a heavy duty pan on a medium heat and pour in the cooking oil. When the oil reaches around 160oC, carefully place as many prawns as you can into the pan but ensure there is a little space between the prawns so they are not crammed in. Cook for 2 minutes, turning halfway through if necessary. Remove the prawns and place them on a plate or tray lined with kitchen paper towels. Repeat this process until all your prawns are cooked.