small, multicolored sturdy tomatoes, such as petite heirloom, kumato or Campari (about 12 ounces total), sliced crosswise ¼-inch thick • Kosher salt and black pepper • packaged puff pastry, thawed (about 7 ounces) • crème fraîche, sour cream or Greek yogurt • small red onion, very thinly sliced • Aleppo pepper, paprika or red-pepper flakes, for garnish • fresh ricotta, squeezed dry • Store-bought or homemade pesto, for drizzling • Extra-virgin olive oil, for drizzling • Fresh basil leaves, for garnish (optional)