How should I store leftover rice noodles?

How are you eating them? For me, reheating these noodles automatically overcooks them and I can never get a good consistency out of repeats. I use leftover noodles one of two ways: in a salad or dropped in soup. For the former, I toss the leftovers in olive oil and store them in the fridge. The oil keeps a protective seal around the noodles so they keep their tooth. The next day, I chop some fresh vegetables and mix in the noodles, and season. In soup, there's no need to prepare them, just drop refrigerated noodle clusters in hot water and they separate. The result is soft noodles, which may not be your preference.

From the point of view of someone who used to work in a Chinese restaurant, we used to prepare vermicelli which are really thin rice noodles by soaking the uncooked dry noodles in cold water for about 1 hour or until it is flexible. We then can store this soaked, but uncooked noodle covered with a plastic wrap in the refrigerator for several days. They don't need to be oiled. To cook it, we just submerge it in boiling water for about a minute and then prepare it however we need it. With the soak it takes practically no time to cook at all.

Perhaps in the future you can follow this method and pre-soak your noodles. Then you can use however much noodles you need from that batch and save the rest for later. Plus it'll save on cooking time.

Just put the leftover rice noodles in a zip lock bag in the refrigerator to store them. When you are ready to use them the next day or so put however many you want into a heat proof bowl and pour boiling water over them. Immediately drain them, put them in the serving bowl and put Thai peanut sauce (which may also be left over) and fresh cilantro on them. Toss them lightly. Fast delicious hot lunch.