Cut out and discard the core at the top of the tomatoes, and chop the tomatoes roughly into quarters. Place in a blender. Peel the cucumber and cut it into chunks. Add them to the blender.

Cut the bell pepper in half, and remove and discard the core and seeds. Chop the pepper into large pieces and place them in the blender. Add the garlic, sherry vinegar, and ½ cup water, and blend until the mixture becomes a thick liquid.

The red tomatoes will have turned a wonderful pink color. Taste for acidity (this will vary with the sweetness of the tomatoes). If it's not balanced enough, add a little more vinegar. Add the olive oil and salt. Reblend. Then pour the gazpacho through a strainer into a pitcher. Refrigerate until cool, at least 30 minutes.

While the gazpacho is chilling, prepare the croutons: Heat 1 tablespoon of the olive oil in a small pan over a medium-high flame and fry the bread until golden on both sides, about 2 minutes. Break the bread into small pieces to form 16 croutons and set aside.

To serve, place four croutons, two fillets of tomato seeds, six cherry tomato halves, three cucumber cubes, and three onion segments in each bowl. Add a few drops of the remaining olive oil to each onion segment, and drizzle a little more oil around the bowl. Add a few drops of vinegar to each cucumber cube, and drizzle a little more around the bowl. Sprinkle sea salt on the tomatoes, and sprinkle the chives over all. Pour the chilled gazpacho over the garnish, at the table.

To make fillets of tomato seeds:
Using a sharp knife, slice off the top and bottom of each tomato. Locate the fleshy dividing wall of one segment inside the tomato. Slice alongside the dividing wall and open up the flesh of the tomato to expose the seeds. Remove the seeds and their pulp by slicing around the core of the tomato. Set the seeds aside. Your aim is to keep the pulp and the seeds together to create tomato-seed "fillets" that are separate from the firmer tomato flesh. Repeat with each segment of the tomato.