Peel the lemons with an appropriate peeler, keeping only the zest with the white pith removed. Blanch these peels in boiling water with a little salt. Refresh in cold water and dehydrate in a 100°F sterilizer for 48 hours.
Chop the peels very finely, put them through a sieve and combine with the sea salt. Set aside in a dry place. (Proportion: 3 g lemon powder to 30 g salt.) Now you have lemonsalt that is perfect for seasoning foods that require both salty and lemony flavours.
For the chips Cut the potatoes into thin slices. Place them in water and rinse 3 or 4 times to remove the starch. Dry well with a kitchen towel.
Deep fry the potato slices in hot oil in a deep pan. Do not fry too many of the chips at once: keep them well separated. Drain and place on paper towels. Sprinkle with lemonsalt. Dry for 3 hours at 195°F.