Toasting the ciabatta: Pre-heat oven to 200°C/392°F. Cut the loaf of ciabatta into 1-inch cubes. Drizzle with 1 tbsp of olive oil and sprinkle with a little salt and black pepper. Bake for 15 minutes or until toasted and golden. Allow to cool.
Grilling peaches: Toss peaches with 1 tbsp of jalapeno brine and 1 tbsp of olive oil. Heat a grill pan over medium heat. Add the peaches and grill all sides until charred. Allow to cool slightly.
Jalapeno vinaigrette: Add all the ingredients of the vinaigrette into a jar and give it a good shake. That's it!
Final touches: Add the toasted ciabatta, grilled peaches, sliced onions and halved cherry tomatoes into a big bowl. Pour the jalapeno vinaigrette over everything and give it a good toss until everything is well-combined. Refrigerate for 1-2 hours or up to overnight. Serve at room tempreture!