Bring a large saucepan of water to a boil; add pumpkin, ginger, and soy sauce. Cook pumpkin mixture for about 3 minutes. Add noodles to pumpkin mixture and cook until noodles are slightly cooked, about 4 minutes.
Stir tofu into pumpkin-noodle mixture and cook until pumpkin and noodles are almost tender, 5 to 10 more minutes.
Place 1 teaspoon miso paste into each serving bowl. Ladle cooking water into each bowl and whisk until miso is dissolved.
Divide pumpkin-tofu soup between the 2 serving bowls; garnish each with 1 teaspoon sesame oil, 1 chopped green onion, 1 sliced red chile pepper, 1 tablespoon sesame seeds, 1 tablespoon cilantro, and 1 tablespoon pickled ginger.