Cut two pieces of greaseproof paper and place one of these onto a baking sheet.
Heat one tablespoon of oil in a pan, and gently fry the chorizo for two minutes on each side, or until golden-brown on both sides.
Once cooked, place the chorizo pieces onto the lined baking sheet. Cover with the additional greaseproof paper and place another baking sheet on top. Finally, place a weight onto the baking sheet and put into the oven to cook for five minutes.
Heat one tablespoon of olive oil in a frying pan cook the salmon for 30 seconds on one side only and remove from the heat.
For the dressing, whisk the sherry vinegar, mustard, oil and garlic together in a bowl until well combined.
For the salad, mix the rocket, watercress and shallot together in a bowl and scatter the chorizo over the leaves.
To serve, spoon the salad onto serving plates, top with the salmon pieces and tomatoes and drizzle with a little dressing.