Bring orange juice to a boil in a saucepan and allow to reduce to by 3/4. Let cool. In a food processor, beat egg then gradually add oil. Process in olive oil, vinegar, lime juice and concentrated orange juice. Process until smooth then season to taste with salt. Refrigerate for 1 hour.
Peel off the whites of the oranges, leaving only the pulp then combine with mint leaves and fennel.
On a plates, place salmon, add the orange pulp mixture on top then drizzle with the orange dressing.