For the dough, place the flour, salt and yeast into a large bowl and stir to combine.
Pour in the olive oil and gradually stir in the water until it forms a soft dough.
Tip the dough out onto a floured work surface and knead for 5 minutes, until smooth and elastic.
Place the dough into a lightly greased bowl, cover with cling film and leave to rise in a warm place for one hour.
Remove the dough from the bowl and knead for a minute on a floured work surface, then divide into four pieces and roll each into a circle 0.5cm/¼in thick.
For the topping, heat a frying pan until hot, and then add the oil, shallots and garlic and fry for 3-4 minutes.
Add the tomatoes, sugar and the chopped basil and bring to the boil. Reduce the heat and simmer for 20 minutes, or until the sauce has thickened. Season, to taste, with salt and freshly ground black pepper and leave to cool.
Preheat the oven to 220C/425F/Gas 7. Place a heavy baking tray or a pizza stone into the oven to preheat.
Place the pizza bases onto an upturned, floured baking tray. Spoon the cooled tomato sauce thinly over the pizza.
Sprinkle over the artichokes, chorizo, mozzarella and half the spinach then season, to taste, with salt and freshly ground black pepper.
Carefully transfer the pizzas into the oven, pushing the pizzas from the floured tray onto the hot tray or pizza stone. Cook for 15 minutes, or until the base is crisp and the topping is cooked through.
Remove from the oven and sprinkle with the remaining spinach leaves.
For the salad, place the spinach and gem lettuce leaves in a large bowl, with the cherry tomatoes.
In a separate small bowl mix together the oil, sherry and red wine vinegar then pour the dressing over the salad.
To serve, place each pizza on a warm plate with the salad on the side.