1. Peel the onion and the carrots.
2. Chop the onion and cut the carrots into thin julienne strips.
3. Chop the chives and mix in a bowl with the fromage frais, lemon juice, salt and pepper.
4. Pre-heat the grill.
5. Cut the salmon fillet into thin escalopes.
6. Lay on an oven tray covered with foil.
7. Brush over half the olive oil and season with salt and pepper.
8. Cut the rolls in half, brush the bottom half with the rest of the oil and toast under the grill.
9. Then grill the salmon escalopes for 2 to 3 mins.
10. Arrange the salad, onion and carrots on the toasted rolls.
11. Pour over chive sauce and then lay the salmon escalopes on top. Serve immediately.