Place prawns, ginger, chillies and leeks in a bowl. Add the flour, paprika and salt. Stir in the water, lime, fish sauce and garlic and mix until you have a batter like consistency. If this is still dry, add more water until the correct consistency is achieved.
Heat the oil in a pan. When the oil is hot, using a tablespoon, add a spoonful of the batter to the oil. This should be fried on both sides for approx 5-7 minutes or until you can see that the pieces of prawn have gone pink. Depending on the amount of batter, you may need to heat more oil to fry the fritters.
The fritters should be golden brown. Place them on a plate with 2 pieces of kitchen paper to absorb excess oil.