Bring a saucepan of salted water to a boil. Cook the pasta until al dente and drain
While the pasta is cooking, make the dressing by whisking all the dressing ingredients together in a small bowl until combined (or shake together in a jar). Set aside.
Prepare and dice the onion, tomatoes, pepper and fresh herbs in a large bowl. Season with salt and pepper and set aside.
Once the pasta has drained, keep it in the colander and run a cold tap, whilst you mix to evenly cool the temperature. Drain all water again once cooled, and set aside.
In your large bowl, mix all of your ingredients until fully incorporated, including the dressing. Serve immediately, or place in an airtight container in the fridge.