Make crust: In a food processor, pulse almond flour, arrowroot, and salt until combined. Add butter and pulse until butter is cut into small pieces and distributed within flour mixture. Add vinegar, honey, and 1 tablespoon ice water; pulse to mix in. Keep adding water 1 tablespoon at a time until a dough forms. Form into a flat disk, wrap, and refrigerate for at least 1 hour or up to overnight.
Make filling: In a small food processor or blender, combine ricotta, honey, mint and salt; process until smooth and whipped, stopping to scrape down sides as needed. Cover and refrigerate.
Preheat oven to 375 degrees F. Place dough between 2 sheets of parchment paper and roll into a 12-inch disk, about 1/16th-inch thick. Don’t worry about making it perfectly round. Carefully peel off top sheet of parchment and slide bottom sheet with rolled-out crust onto a baking sheet. Pat peach and tomato slices dry. Spread ricotta mixture over crust, leaving a 1½-inch border around edges. Decoratively arrange peach and tomato slices over ricotta mixture. Using the parchment to help, gently fold edges of dough around filling (center will remain exposed). Patch any pieces that crack (it doesn’t matter if it isn’t super neat, it’s meant to be rustic.)
Brush egg wash over the edges of the crust (you won’t use all of it) and drizzle the honey over the fruit. Bake until crust is golden, about 30 to 40 minutes, covering loosely with foil if crust is browning too quickly.
Drizzle top of galette with 2 teaspoons olive oil. Let cool for 5 to 10 minutes. Then, sprinkle lightly with flaky sea salt, garnish with mint, if desired, and serve.