Heat 2 tablespoons vegetable oil in a large skillet over medium heat. Add 4 thinly sliced scallions (pale parts only; reserve the dark parts for topping) and cook until softened, 2 minutes. Add one 15-ounce can cannellini beans (drained and rinsed) and 3 tablespoons miso paste and cook, stirring, until coated, 2 to 3 minutes; season with pepper. Remove from the heat and stir in 4 teaspoons soy sauce and 1 teaspoon superfine sugar; cook until glazed. Puree the bean mixture in a food processor with one 14-ounce package soft tofu (drained) and 3 tablespoons rice wine vinegar. Chill before serving. Top with the reserved scallion greens and sesame seeds.