For the dressing:
Combine sour cream, honey, seeded mustard, dijon mustard, lemon juice and salt in a small bowl and stir.
For the salad:
Place potatoes in a large bowl and crumble salmon fillet over the top, toss to combine.
Place a bunch of rocket, parsley and tarragon on a large plate. Top with the potato mix and dollop the dressing around the plate.