To make the dressing, whisk together all the ingredients in a small bowl and set aside.
To make the croutons, put the ciabatta in a bowl, toss in the olive oil and sprinkle with the paprika, then transfer to a baking sheet. Place in a preheated oven, 200°C (400°F), Gas Mark 6, for 10 minutes or until golden.
Meanwhile, heat the sunflower oil in a large frying pan, add the eggs and fry to your liking, then remove and keep warm. Put the chorizo in a separate frying pan and dry-fry over a medium heat for 3–4 minutes or until crisp and cooked through.
Put the chorizo and spinach in a large bowl, drizzle over a little of the dressing and toss to mix well. Divide between 4 serving plates, then top each with one-quarter of the croutons and an egg. Drizzle with the remaining dressing. Season to taste and serve immediately.