I replaced the tuna with salmon in this fresh spring salad.
We first cook the fries in water with the addition of salt and sugar. The water needs to taste like seawater or even a bit more. I guess 30-50g of salt and 30-50g of sugar per liter of water will do fine. Put the fries in the cold water and cook them slowly until they are really tender, but not too much so they start breaking up. Transfer them to a colander and immediately rince them with cold water (to stop the boiling process).
I leave them to cool down in the fridge for the rest of the day. Cooling them down sets the starches inside the potato. You can now fry them on 140° until they turn very lightly brown in colour. Or until there is no more steam coming from the fries. Again, transfer them to a colander in the fridge till the next day. The fridge acts as an airconditioning system so it extracts the water from the fries. For cooking them I use a mixture of pork fat and cow fat.
The next day, your fries will look dehydrated, and that's the point. They're now ready to fry.
You can now fry them on 180°. I prefer to use vegetable oil for this step as the fries are much crispier then when the final fry happens in fat.
I serve them with a little Kewpie mayo!
If you don't use this technique and want to use the classic approach : this is what rinced (with water) fries look like vs. non-rinced (on the left). If you rince the starch off you will get these yellowy beautiful fries vs. stained browny ones.