Pre-soak the bean thread noodles with clean water for 10-15 minutes until soft. And then cook in boiling water for around 30 seconds (If you want it to be softer, cook for another 30 seconds). They become soft quickly after soaking.
Clean spinach and remove the hard roots. Add a small pinch of salt and several drops of oil in boiling water, and then blanch the spinach and shred carrots for 20-30 seconds. Transfer out and soak in cool water. Squeeze the extra water out.
In a small bowl, smash the garlic cloves and then add 1/2 tablespoon of hot water. Soak the garlic for half minute and then mix all the other seasonings. Set aside.
Place bean thread noodles, spinach, carrots and dressing sauce in a large bowl. Combine well and then serve cold.