Snap off and discard the tough ends of asparagus. Bring a medium saucepan of salted water to a boil; prepare an ice bath. Cook asparagus until bright green and just tender, 2 to 3 minutes. Transfer immediately to ice bath. Drain; place on a clean kitchen towel.
In a large bowl, combine asparagus, cucumber, tomatoes, red onion, olives, capers, and bread; toss to combine.
In a small bowl, whisk together red-wine vinegar and olive oil; season with salt and pepper. Pour vinaigrette over asparagus mixture, and toss until well coated. Let sit until bread absorbs juices, and serve.