Peperonata is an Italian mixture ofstewed sweet peppers, tomatoes,onions, and garlic. In this dish, thepeperonata is combined with classicProvencal ingredients to make a flavorful topping for toast.
Preheat oven to 400 degrees. Heat oil in a large nonstick saute pan. Add the onion and garlic; saute, stirring frequently, over medium heat until lightly browned, about 8 minutes. Add bell peppers and paprika; continue cooking until peppers are soft and juicy, about 30 minutes. Season with salt and black pepper.
Meanwhile, place bread on a baking sheet; toast in middle of oven, flipping halfway through, until bread is golden brown on both sides, about 12 minutes.
Prepare an ice bath; set aside. Place eggs in a medium saucepan; add enough water to cover by about 1 inch. Bring to a full boil, and cook for 1 minute. Turn off heat, cover, and let stand for 12 minutes. Transfer eggs to ice bath until cool. Peel eggs; slice each about 1/4 inch thick.
Spread the red-pepper mixture over slices of toast; top with tuna, dividing evenly. Place a few slices of egg on top of the tuna. Season with fleur de sel or sea salt, if using, and black pepper. Garnish with capers, and zest the lemon over the top just before serving.