Slice red onion thinly and place into a bowl of water to take the bite out. Set aside.
Wash green beans and remove ends. Chop into 3-4 in long pieces.
Blanche green beans by dropping into boiling water for 2 minutes, then shock them in ice water to stop the cooking.
Remove from ice water and set aside.
Fry bacon until crisp.
To make the panzanella, chop white or sourdough bread into 1 inch cubes. Toss with olive oil and Italian seasonings. Broil for 5 minutes, tossing once, until bread is crisp.
To make dressing, whisk together olive oil, garlic salt, Italian seasoning, mustard, and vinegar.
In a large bowl, toss green beans with bread, tomatoes, red onion, and crumbled bacon with dressing. Serve immediately.