ON a large serving platter or in a large shallow bowl, combine tomatoes, capers, and chiles. Drizzle with olive oil, salt, and pepper; toss gently to combine.
TOP with tuna. Drizzle with vinaigrette. Sprinkle with sesame seeds, basil, and a little bit of flaky salt if desired. Serve immediately.
*Note: For the prettiest salad, use a mix of tomato colors and types. Cut cherry, pear, or grape tomatoes in half. Cut large tomatoes in chunks or wedges.
**Toast sesame seeds in a small skillet over medium heat for 3 to 4 minutes.