Chop the tomatoes, and put them in a bowl with 1 teaspoon of Maldon or kosher salt (or only 1/2 teaspoon of table salt).
Cut the bread into cubes, drizzle 2 tbsp of olive oil, and toast them at 390°F (200°C) for about 10-12 minutes until they’re golden.
Make the vinaigrette by whisking 2 tbsp of vinegar while very slowly drizzling in the 6 tbsp of olive oil. Season with 1/2 tsp of black pepper.
Add the toasted bread cubes to the tomatoes and let them absorb the tomato juice.
Add the vinaigrette, chopped cucumber, and thinly sliced red onion to the bowl with tomatoes and bread and mix. Let the salad sit for at least 30 minutes in the refrigerator.
Add the freshly chopped basil before serving and toss one more time. Taste and add any additional salt and black pepper you need.