Shell prawns, leaving tail unshelled. Slit prawns halfway lengthwise and remove dark veins. Season with 1 tbsp ginger juice, a pinch of salt and a dash of pepper. Set aside.
Combine A in a bowl and mix till well blended. Stand for 5 minutes.
Heat oil in a wok. Dip each prawn into batter and fry till light golden brown. Remove to absorbent paper to drain oil and place on a serving dish. Arrange cucumber and tomato slices around edge of plate and serve.