Put the chopped tomatoes in a bowl and season well. Add the garlic, capers and red onion. Toss with the tomatoes and set aside for 10 minutes to allow the flavours to mingle.
Arrange the ciabatta chunks in a serving bowl and drizzle over 2tbsp oil, 1tbsp vinegar and season.
Add the tomato mix, and toss with the ciabatta. Add the basil, the remaining oil and vinegar, stir and serve.