Heat the oven to 350°F.

• Finely chop, press, or grate enough garlic to measure 1 teaspoon [2 tsp].
• Cut the ciabatta rolls in half horizontally, then cut the halves in half on the diagonal.

In a small bowl, stir together the garlic and 1 to 2 tablespoons oil. Season with salt and pepper. 

On a sheet pan, place the ciabatta, cut sides up, and brush with the garlic mixture. Toast in the oven until golden brown, 8 to 10 minutes. Meanwhile, prepare the chard.

• Remove any pulp from the preserved lemon and discard; finely chop the peel. 

In a large frying pan over medium-high heat, warm 1 to 2 teaspoons oil until hot but not smoking. Working in batches if needed, add the chard, season with salt and pepper, and cook, stirring occasionally, until starting to soften, 2 to 4 minutes. Add more oil between batches if needed. Remove from the heat, stir in the preserved lemon peel, and season to taste with salt and pepper. Transfer the chard to a medium bowl and cover to keep warm. Do not clean the pan. While the chard is cooking, prepare the remaining ingredients.

• Peel and thinly slice enough onion to measure 1 cup [1½ cups].
• Rinse the chickpeas. 
• Coarsely chop the walnuts for garnish.

In the same pan used for the chard, warm 2 to 4 teaspoons oil over medium-high heat until hot but not smoking. Add the onion and Moroccan spice blend, season with salt and pepper, and cook, stirring occasionally, until fragrant and the onion starts to soften, 2 to 3 minutes. Add the chickpeas and tomatoes and bring to a boil, then reduce to a simmer. Cover and cook, stirring occasionally, until the chickpeas are heated through and the sauce is thickened slightly, 2 to 3 minutes. Remove from the heat and season to taste with salt and pepper. 

Transfer the garlic toasts to individual plates. Top with the chard, then the chickpeas and sauce. Garnish with the walnuts and serve as open-faced sandwiches.