Don't worry about making the crumbs uniform; there's more textural goodness to be had when the crumb size varies. Tear about 1/4 of a good loaf of rustic white bread (fresh or day-old) until you've got 2 cups 1" crustless breadcrumbs. Pulse in a food processor until crumbs are coarse. Toast crumbs in about 3 tablespoons olive oil in a large skillet over medium-high heat, tossing frequently, until crunchy and golden brown, about 5 minutes. Season with kosher salt and let cool on a paper towel-lined plate. DO AHEAD: Breadcrumbs can be made 1 day ahead. Store airtight at room temperature.