STEP 1

In a medium bowl, season the tuna lightly with salt and toss to coat. Set aside.

STEP 2

To a large pot set over medium heat, add the oil; when the oil is hot, add the bell pepper and onion and cook, stirring occasionally, until the onion is softened and translucent, 8–10 minutes. Add the potatoes and garlic, season with salt, and continue cooking until vegetables are softened but not colored, 3–5 minutes. Add the pimentón and 3 cups water and bring to a simmer. Cook until the vegetables are tender, 13–15 minutes. Turn off the heat, add the tuna, and immediately cover the pan. Set aside until the fish is just barely cooked through, 3–5 minutes.