In a large mixing bowl, combine the oats with the orange juice and apple juice, making sure the oats are completely covered with juice, and let soak until the oats are very soft, about 30 minutes.
While the oats are soaking, preheat the oven to 375°F and line a large rimmed baking sheet with parchment paper.
Drain the oats, reserving the juice, and return the oats to the large bowl. Put the reserved juice in a small bowl, add the currants, and soak for about 15 minutes while you prepare the rest of the cereal.
Stir the oats vigorously with a fork until they break down and become a thick batter. Add the salt, sugar, wheat germ, flax seeds, sunflower seeds, dates, coconut, and hazelnuts. Drain the currants (discarding the liquid this time) and add those to the mix, too. Stir to combine well.
Scrape the thick cereal batter into the prepared pan and press it into an even rectangular slab thin enough so that you can see the tops of the hazelnuts peeking out. Bake for 20 minutes, until the batter is set, dry to the touch, and starting to brown at the bottom.
Remove the pan from the oven and let the cereal cool in the pan until cool enough to handle. Meanwhile, preheat the oven again, this time to 200°F Remove the parchment paper from the baking sheet and discard.
Break the sheet of cereal up into thirds with your hands. Place about 1/3 of the cooled cereal into a food processor fitted with the metal blade and give it 20 to 25 pulses, until the cereal is broken into pieces slightly smaller than peas. Transfer the chopped cereal into another vessel and pulse the remainder of the cereal in two more batches.
Spread the cereal on the baking sheet in a single, even layer. Place in the oven and let dry for 30 minutes. Remove the pan from the oven, stir the cereal, spread it out again, and return to the oven to dry for another 30 minutes.
The cereal is now ready to eat.
Allow it to cool completely in the pan before transferring to an airtight container. It will keep for at least 3 months in the refrigerator.