2 pounds beefsteak tomatoes (about 4), quartered
1 large English hothouse cucumber, peeled, seeded, cut into pieces
1 large ripe peach, peeled, halved
½ jalapeño, seeded (or with seeds for a spicier soup), chopped
½ garlic clove
1 cup fresh (or frozen, thawed) cherries (about 8 oz.), pitted
2 Tbsp. (or more) white balsamic or Sherry vinegar
¼ cup extra-virgin olive oil plus more
1½ tsp. kosher salt plus more
Freshly ground black pepper
Flaky sea salt (such as Maldon)