For the filling, finely chop all ingredients (best with a hand mixer or food processor, a kitchen knife works just as well). Do not season with salt.
Cut the unpeeled zucchini lengthwise into narrow strips (best done on a vegetable slicer or with a slicing machine). Put these strips in salted water for one minute and then rinse them in water with ice cubes.
Brush 4 sheets of aluminum foil (30 x 50 cm) with a little bit of olive oil. Put on them (overlapping) 3 slices of zucchini each, on top of each a fillet, season it with pepper and lightly season it with salt. On the fillet form each 2 tbsp. of the filling. Next, carefully roll up the aluminum foil from one side of the zucchini ends. But of course, do it in such a way that the foil does not roll up into the stuffed fish with it. Twirl the ends of the foil together like a candy. Put these thick sugar cubes into a very hot frying pan with a little bit of oil and fry them for about two minutes. With the frying pan you put the rolls for 8 to 10 min in the stove heated up to 175 degrees.
Grind the ingredients for the olive tapinade also in a food processor or with a hand blender.
Press the cooked potatoes through a press or mash them very finely. Add olive oil. Season to taste with salt and freshly ground pepper.
For the sauce, add the onion w