Heat oven to 350 degrees. Slice or tear the bread into 1-inch pieces and spread on a baking sheet. Drizzle the bread with the 2 tablespoons oil and bake until the bread is crisp and golden, about 15 minutes. Cool, then pulse in a food processor or blender to make coarse crumbs, or put into a heavy duty zip-top bag and bash with a rolling pin or heavy pot.
For the squid and spaghetti:
Turn the oven up to 475 degrees. Put the squid, olive oil, garlic, red pepper and 1/2 teaspoon salt in a large bowl and toss together.
Bring a large (at least 6 quarts) pot of water to a boil, adding 3-4 tablespoons kosher salt (or 1 tablespoon table salt) to the water.
When the oven is hot, place a large rimmed baking sheet on the rack to heat up for 10 minutes.
Carefully pour the squid onto the hot baking sheet in an even layer - the pan might buckle at this point, but don't worry. Distribute the tomatoes over the squid and roast 8-10 minutes, until the squid is opaque and the tomatoes shrivel and begin to caramelize.
Meanwhile, cook the spaghetti until al dente, drain and transfer to a large serving bowl.
Pour the squid and tomatoes over the spaghetti, along with all the pan liquid. Toss to combine (add more olive oil to taste if the pan seems dry).
Top with the breadcrumbs and fresh herbs.
Don't like squid? Try this method with shrimp instead!