Halve the tomatoes crosswise. Squeeze the seeds into a sieve set over a bowl. Press on the seeds to extract the juice; discard the seeds. Cut the tomatoes into large chunks. In a food processor or blender, puree the tomatoes with 1/2 cup of the strained juice. Add the garlic, jalapeño, vinegar and half each of the diced red onion, celery and cucumber and process until smooth. Transfer the gazpacho to a bowl. Stir in the remaining diced red onion, celery and cucumber and season with salt and pepper. Pour into small glasses, drizzle with olive oil and serve.