In a mixing bowl, combine all-purpose flour and salt, creating a well in the center. Pour in hot boiling water and stir until a shaggy dough forms. Transfer the dough onto a floured surface and knead for about 10 minutes, until smooth and elastic. Cover the dough with a damp cloth and let it rest for 30 minutes.

While the dough is resting, prepare the filling. Drain and press the firm tofu until dry, then crumble it into a bowl. Sauté chopped green beans in a splash of oil for 2-3 minutes until just tender. Combine with the crumbled tofu, grated carrot, chopped cilantro, sesame oil, salt, and white pepper. Mix thoroughly and divide into 10 equal portions.

Roll the dough into a log and cut it into 10 equal pieces. Flatten each piece into a round wrapper about 4 inches in diameter. Place one filling portion in the center of each wrapper and fold the dough over, pleating it to seal well. Moisten the top with a dab of water and press sesame seeds into it.

Heat a non-stick pan over medium heat and add enough oil to coat the bottom. Place the assembled buns in the pan, slightly flattening them. Sauté until the bottom turns golden and crispy, about 4-5 minutes. Add enough water to cover one-third of the buns, cover the pan with a lid, and steam for 3-5 minutes. Alternatively, bake at 375°F (195°C) for 20-25 minutes, flipping halfway through.