• Peel the onion and cut in half lengthwise, then crosswise into ¼-inch-thick slices. Measure ¼ cup [½ cup] onion and set aside for the soup.

In a large frying pan over medium-high heat, warm 1 to 2 tablespoons oil until hot but not smoking. Add the remaining onion, season with salt and pepper, reduce the heat to medium, and cook, stirring occasionally, until the onion is softened and caramelized, 12 to 14 minutes.
While the onion cooks, prepare the soup.

• Rinse the chickpeas and kidney beans.
• Coarsely chop enough dill to measure 1 tablespoon [2 TBL]. Set aside any remaining dill for garnish or save for another use.
• Coarsely chop the cilantro.
• Cut the lemon into wedges for garnish.

In medium [large] sauce pot over medium-high heat, warm 1 tablespoon [2 TBL] oil until hot but not smoking. Add the ¼ cup [½ cup] onion, season with salt and pepper, and cook, stirring occasionally, until starting to soften, 3 to 4 minutes. Stir in the turmeric and cook until fragrant, about 30 seconds. Add the chickpeas, beans, and 2 cups [4 cups] water and bring to a boil. Reduce to a simmer and cook, stirring occasionally, until the chickpeas and beans are warmed through and starting to soften, 3 to 4 minutes.
While the soup cooks, prepare the ciabatta.

• Cut the ciabatta in half horizontally.

Move the onion to one side of the frying pan. Working in batches if needed, place the ciabatta, cut sides down, in the pan and cook over medium heat until lightly browned, 3 to 4 minutes. Transfer the ciabatta to a cutting board and cut into 1-inch-wide strips. Season to taste with salt and pepper.

Remove the pot with the soup from the heat and stir in the dill, cilantro, and spinach. Season to taste with salt and pepper.

Transfer the soup to individual bowls and top with the caramelized onion. Garnish with any remaining dill, if desired. Serve the lemon wedges and toasted ciabatta on the side.