Fill a roasting dish with 5cm warm water and place haloumi slices in it in a single layer. Leave at room temperature for 2 - 6 hours, or over night in the fridge.
Thinly slice the chilli and place in a small pan with the garlic and half the oil. Bring to a gentle simmer for 2 minutes. (You don't want the garlic to change colour too much, you just want the flavours to infuse). Take off the heat and pour contents into a small jug, then add the reamining oil and the vinegar and leave this dressing to one side.
Bring a small pot of water to the boil and add half the spinach and submerge with a wooden spoon. Keep the spinach in the water for 15 seconds then drain immediately into a strainer and refresh with cold water. Squeeze out excess water. Shred the remaining spinach with a shap knife.
Take the haloumi from the soaking water and pat dry on kitchen paper. Heat a frying pan and add a few tablespoons of olive oil, then fry the haloumi on both sdies. Remove from the heat and place on 4 plates.
Take the blanched spinach and pull apart to loosen it a little, then place in a bowl with the shredded raw spinach, orange sements, hazelnuts and sun dried tomatoes.
Slice the water chestnuts into rounds about 5mm thick and add to the bowl.
Stir the chilli dressing and add to the salad mix with a little salt and mix by hand.
Divide the salad between the four ptaes and serve.