Wash the tomatoes and slice them into chunks, if they are cherry tomatoes, you can just halve them. Peel the red onions and slice them into thin rings, which you can then halve. Wash the coriander and chop coarsely. Mix the tomatoes, onion and coriander in a bowl and season with salt, pepper, a splash of olive oil and Worcester sauce. Enjoy as a simple side salad with any meal.