In a large skillet or sauté pan, heat 2 tablespoons of the oil over medium-high heat. When it shimmers, add the bread crumbs and a pinch of salt and stir well. Cook, stirring and tossing constantly, until nicely browned, 2 to 3 minutes. Scrape into a bowl and set aside.
Return the skillet to medium-high heat and add the remaining 1 tablespoon oil. Add the mustard seeds, then the tomatoes and a good pinch of salt, and toss well. Cover and cook, tossing occasionally, until the tomatoes have softened and are nicely browned but still hold their shape, about 7 minutes. Transfer to a serving bowl and top with the bread crumbs. Serve.