Tonnato with Tomatoes

Ingredients

• 2 pounds mixed heirloom tomatoes, thinly sliced
• 1 and 1/2 pounds small tomatoes, such as Campari or cherry tomatoes, halved
• kosher salt
• 3 to 4 lemons
• 1 clove garlic, peeled
• 1 (5- to 7-ounce) tin or jar oil-packed tuna, such as Tuscanini
• 4 oil-packed anchovy fillets
• 1/2 cup Gefen Mayonnaise, plus more as needed
• 2 tablespoons Haddar Dijon Mustard
• 2 tablespoons brined capers, drained
• freshly ground black pepper
• extra-virgin olive oil, for serving
• flaky sea salt, for serving
• chile flakes, for serving (optional)