In a food processor, combine flour with sea salt. Pulse in cold unsalted butter until the mixture resembles coarse crumbs. Add ice water and vinegar, mixing until a dough forms. Chill for at least 2 hours.

Slice heirloom tomatoes and toss with sea salt. Let sit for 30 minutes to draw out moisture, then pat dry.

In a bowl, combine goat cheese, olive oil, chopped chives, thyme leaves, minced garlic, and lemon zest. Mix until creamy and well-blended.

Preheat oven to 400°F (200°C). Roll out the chilled dough on a floured surface into a 12-inch circle. Transfer to a parchment-lined baking sheet.

Spread the goat cheese mixture over the dough, leaving an inch around the edges. Layer with sliced tomatoes. Fold edges over filling and brush with egg wash.

Bake for 40-45 minutes or until golden brown. Check during the last minutes to prevent over-browning.

Cool for 10 minutes, garnish with fresh basil and flaky sea salt, slice, and serve warm.