Wash the tomatoes then cut each into quarters and add to a bowl. Drain the black beans, rinse with running water and drain again before adding to the bowl. Continue by heating a dry frying pan then add the corriander seeds and, constantly stirring, heat until they start to smoke or pop. Transfer to a blender and grind to a powder then add to the bowl with the fenugreek, salt and pepper. Finally juice the lime then measure the oilive oil into a bowl. Slowly pour in the lim juice while whisking until it is all mixed together then add to the bowl, mix everything thoroughly and serve.