Put the tomatoes in boiling water for 30 secs to make peeling easier and dice it in small chunks Peel cucumber and dice it small. Dice pepper and garlic cloves very small. Mix all the vegetables in a food processor starting with tomatoes until it gets soup consistency. Add the vinegar and pour oil slowly without stopping the mixer. Add some cold water if the mix gets thick. Gazpacho should be a soup, not a cream. Add salt to taste. True spanish gazpacho don´t need onion, but you can add some if you like it. Serve cold.