1.Make mint and lemon dressing. Peel lemons thinly with vegetable peeler, avoiding white pith. Cut rind into long thin strips. Place rind in small saucepan; cover with water, bring to the boil. Drain and repeat. Segment lemon over small bowl to catch any juice. Blend or process lemon segments with remaining ingredients, until chopped finely. Transfer to small bowl, stir in rind.
2.Shell and devein prawns, leaving tails intact.
3.Combine prawns with remaining ingredients in large bowl. Just before serving, drizzle with dressing.
Depending on the tartness of the lemons, you may need to add a little more sugar to the dressing.