1.To make wasabi mayonnaise dipping sauce, whisk sauce, mirin, vinegar and wasabi in small bowl until smooth; whisk in mayonnaise. Refrigerate until required.
2.Press tofu between two chopping boards with weight on top, one end; stand 25 minutes.
3.Discard skin and bones from salmon; coarsely mash in medium bowl. Stir in tofu, onion, ginger, garlic, flour, sauce, mirin and egg until combined.
4.Heat oil in large saucepan; deep-fry tablespoons of salmon mixture, in batches, until golden. Drain on absorbent paper.