Preheat the oven to 400 degrees F. Line a sheet tray with nonstick aluminum foil. Line a second sheet tray with parchment paper.
Spread the cubed bread on the sheet tray lined with parchment paper. Place the chorizo slices on the sheet tray lined with foil, leaving space between each piece.
In a medium bowl, combine the tomatoes, 2 tablespoons olive oil, a generous pinch of salt and pepper, the red pepper flakes, lemon zest and Italian seasoning and stir to combine. Transfer to the sheet tray with the chorizo and spread out in an even layer.
Place both sheet trays in the oven. Bake the bread cubes until toasted, 8 to 10 minutes. Roast the tomatoes and chorizo until the chorizo is cooked through and the tomatoes start to release their juices, 20 to 25 minutes.
In a large bowl, combine the toasted bread cubes and roasted tomatoes and chorizo with the liquid on the sheet tray. Add the remaining 3 tablespoons olive oil along with the scallions and cilantro and toss to combine. Add a little more olive oil if needed. Let sit until ready to serve. Transfer to a serving bowl.