For the roasted cauliflower: Put a baking sheet in the oven and preheat to 450 degrees F.
Meanwhile, toss together the cauliflower florets, olive oil and za'atar in a medium bowl. When the oven is at temperature, pour the cauliflower onto the hot baking sheet, making sure to scrape out all the oil and za'atar. Bake for 10 to 12 minutes, until the cauliflower is crispy and tender. Let cool slightly.
For the toast: Preheat a grill or grill pan over medium heat. Lay the sliced bread out on a clean work surface, brush on both sides with oil and season with salt. When the grill is hot, add the bread and grill for 1 to 2 minutes per side, until the bread is charred and toasted. Remove to a baking sheet.
For the avocado: Place the avocado, 3 tablespoons of the Fresno chile, and the garlic in a large bowl. Mash together with the back of a fork until evenly incorporated but still chunky. Stir in the lime juice and season with salt. Let sit for 5 minutes, then taste and adjust the salt and lime juice as needed. You can also stir in the remaining 1 teaspoon Fresno chile for more heat!
For the labne: Mix together the labne and honey. Set aside.
To assemble: Divide the avocado mixture evenly over the toasts, spreading it to the edges. Top with the labne, leaving a 1-inch border. Add a few pieces of roasted cauliflower to each toast. Serve immediately.