Soak the Dried Choricero Peppers (Pimiento Choricero) in hot water for 20 minutes until softened; remove seeds and skins, then scrape out the pulp and set aside (reserve a little soaking liquid).
Peel and cut the Potatoes into large bite-size chunks and rinse to remove excess starch.
Finely chop the Onion and Green Bell Pepper; thinly slice the Garlic.
Heat a generous glug of Extra-Virgin Olive Oil in a heavy pot over medium heat and sweat the Onion, Green Bell Pepper and Garlic until soft and translucent, about 6–8 minutes.
Stir in the Sweet Paprika for 30 seconds to bloom the spice (don’t let it burn), then add the chopped Ripe Tomatoes and the scraped choricero pulp from step 1; cook until the tomatoes break down, 6–8 minutes.
Pour in the Dry White Wine to deglaze the pot, scraping up any browned bits, and simmer until the alcohol smell fades, about 2–3 minutes.
Add the Fish Stock, a Bay Leaf, and the Potatoes (and a little of the reserved choricero soaking liquid if the broth looks thin). Bring to a gentle simmer and cook until the potatoes are almost tender, about 12–15 minutes depending on size.
Season the broth with Salt and freshly ground Black Pepper to taste.
Cut the Fresh Tuna (Bonito) into large cubes and gently stir them into the simmering stew. Cook just until the tuna is opaque and cooked through — typically 3–5 minutes for large pieces.
Taste and adjust seasoning, remove the Bay Leaf, and let the stew rest for a minute so flavors meld. Serve hot with crusty bread and spoonfuls of the flavorful broth over the tuna and potatoes.
