Soften the bean threads in a bowl of boiling water for 2 minutes. Drain and cut into 15 cm lengths.
Chop the onion with the food processor, set aside.
Chop the tomato with the food processor, set aside too.
Melt the butter in a large sauce pan, add the onion, tomato, pork and the water, simmer over low heat until tender.
Add the bean threads, chili pepper and salt and pepper.
Simmer until heated through.