Place the spinach and celery leaves in a steamer and cook for 10–15 minutes until soft. Refresh under cold running water, then drain well and squeeze out the excess water. Chop to a fine pulp.
Heat the oil in a heavy-based frying pan, stir in the garlic and cumin seeds and cook until they emit a nutty aroma. Stir in the olives, parsley, coriander and paprika. Add the spinach and celery leaves, season well and cook gently for 8–10 minutes until the mixture is smooth.
Meanwhile, cook the haloumi. Heat the oil in a separate heavy-based frying pan, add the haloumi and fry for 3–4 minutes, turning once, until golden brown and crispy. Drain on kitchen paper.
Tip the spinach mixture into a bowl, add the lemon juice and mix well. Serve warm with the fried haloumi.