Preheat the oven to 450° with 1 rack in the upper third and another in the lower third. In a small bowl, whisk 2 Tbsp. oil with the lime juice, za'atar, honey, sumac, and allspice. Season with salt and pepper. Pour onto a large rimmed baking sheet, and add the asparagus and shallot. Toss to coat, and spread in an even layer.
On another rimmed baking sheet, toss the bread cubes with the remaining 2 Tbsp. oil, and season with salt and pepper. Spread in an even layer.
Place the asparagus sheet on the top rack and bread cubes on the bottom. Roast until the asparagus is tender (stirring halfway), about 20 min., and the croutons are crisp and light golden, about 15 min. Remove trays when they are done.
Meanwhile, in a medium bowl, whisk together the goat cheese and yogurt. Season with salt and pepper.
Spread the goat cheese mixture on the bottoms of 4 plates, and top each with 1/4 roasted asparagus mixture and croutons. Serve with lime wedges.
Recipe by Laura Rege.