Cook pasta in a large saucepan of boiling salted water following the packet directions until tender and then drain but reserving 1/2 cup of the cooking liquid.
Return pasta to pan.
Meanwhile heat oil in a large frying pan over medium high heat and add garlic and chili and cook for 1 minute or until fragrant and then add prawns and cook stirring for 2-3 minutes or until pink and cooked through.
Add tomato and cooking liquid and cook for 2 minutes or until heated through.
Season with salt and pepper ad stir through the parsley and then serve.