Dice the shallot and add it into a bowl with the vinegar, which will pickle it slightly.
Slice the tomatoes in half and place them in a sieve over the bowl, and sprinkle over the salt. Leave them for 30-45 minutes, stirring occasionally. The salt will draw out the water from the tomatoes, which will drip into the bowl below. Meanwhile, the shallots will be pickling slightly in the vinegar.
Heat the oven and cut the bread into small, bite-sized pieces. Lay the bread out on an oven tray and bake in the oven for 10-15 minutes, just long enough to dry it out completely and make it crunchy.
Cut each of the peaches into 4-5 segments.
Heat a griddle pan and wipe some olive oil over it to prevent the sugar in the peaches from sticking. When it is really hot, sear the peaches on all sides. Watch that they do not burn.
Peel and cut up the cucumber and crumble the feta into small pieces.
Make the Panzanella dressing by whisking the olive oil and mustard into the tomato juice/shallot/vinegar mixture and season to taste. You will not need to add much salt to this Panzanella Salad as the tomatoes have been salted already.
Assemble the Peach Panzanella Salad by adding all the ingredients to a large bowl, pouring over the dressing and garnishing with fresh basil leaves and crumbling over the feta.