Preheat the oven to 175°C with a rack set on the middle shelf.
Drain the tuna, reserving the oil, about 1/3 cup. If you do not have 1/3 cup oil from the tuna, add enough extra-virgin olive oil to yield 1/3 cup.
Use your hands to tear the bread slices into large pieces and put in the bowl of a food processor. Pulse until only fine crumbs remain, about 2 cups. Place the breadcrumbs on a baking sheet and toss with the reserved tuna oil. Season liberally with salt. Bake until light golden brown and crispy, 10 to 12 minutes, gently tossing the crumbs occasionally. Cool slightly on a cooling rack, and then use your hands to break up any large chunks.
Meanwhile, bring a large stockpot of salted water to a boil (it should taste like sea water).
While the water is coming to a boil, make the pasta sauce. Heat the olive oil in a large, straight-sided skillet over medium heat. Add the garlic and a large pinch of crushed red pepper flakes. Cook until the garlic softens and starts to lightly brown, 2 to 3 minutes. Add the grape tomatoes, capers and white wine. Increase the heat to medium-high and cook until the tomatoes start to soften and the wine is reduced by half, 4 to 6 minutes. Add the romaine and drained tuna. Season liberally with salt and cook until the romaine is completely wilted and the tuna is heated through, 3 to 5 minutes, stirring occasionally. Turn off the heat.
Cook the pasta in the salted boiling water until al dente. Reserve 1/2 cup of the pasta cooking water, and then drain the pasta.
Toss the pasta with the tuna sauce in a large mixing bowl. Use as little or as much of the reserved pasta water to loosen the sauce to your taste. Season with additional salt and crushed red pepper flakes if needed.
To serve, divide the pasta among 4 to 6 plates, top with the toasted breadcrumbs and drizzle with additional olive oil.