In a bowl whisk the zest and the orange juice with salt to taste.
Whisk until the salt is dissolved.
Add the oil in a stream while whisking.
Whisk the dressing until it is emulsified.
In another bowl toss the fennel with half the dressing until it is coated well.
Add the watercress and apricot to the remaining dressing.
Toss it until it is just coated well.
Divide it between 2 plates.
Mounding the fennel in the middle.