Start this recipe by placing the cherry tomato halves on a baking tray flat side up. Drizzle with olive oil, sprinkle over oregano and season well with salt and pepper. Place into the oven and roast at 150`c for 20-25 minutes. Meanwhile, pan fry the salmon on both sides to seal and continue cooking in the oven for 10 minutes. When the salmon and tomatoes are cooked, remove from the oven and start cooking the pasta shells in a pan of salted boiling water. When cooked, drain and mix in the pesto. Flake the salmon and add to the pasta, along with the roasted tomatoes and basil leaves. Carefully mix together and serve into 2 bowls with lime wedges on the side and chopped pistachios on top.