Heat the 1/4 cup olive oil in a large saute pan or deep skillet over medium heat until shimmering. Add the onions and chopped garlic and season with salt and pepper. Cook, stirring occasionally, until softened and just starting to brown, 6 to 8 minutes. Add the chorizo and cook, stirring occasionally, until slightly rendered, 3 to 5 minutes.
Crush the tomatoes by hand and add them to the pan along with their juices. Stir in the chipotle and paprika, then stir in the chickpeas and roasted red peppers; season with salt and pepper. Bring to a simmer over medium heat, then nestle the cod in the stew. Cover and simmer over medium-low heat until the cod is cooked through, about 5 minutes.
Meanwhile, preheat a cast-iron grill pan over high heat. Brush the bread with olive oil and grill, flipping once, until lightly charred, 3 to 5 minutes. Rub the grilled bread with the whole garlic clove and season with salt and pepper.
Garnish the stew and bread with the parsley and serve right away.