I would not be opposed to taxing their assets. But confiscating things right away is not the way to go. Let the refugees figure out themselves how to pay the taxes, what to sell, what not to sell.
Waivers should be given for those paying for school or paying for certification tests to help expand opportunities for employment. They don't want to have to pay for them, then don't make it difficult for them to get jobs.
Refugees often leave with their clothes on their back and little more. If they actually manage to take things with them, it would be hard to imagine that those items didn't have significant personal value. It seems crude and inhumane that anyone would consider confiscating personal property. Refugees lost a lot of their dignity when they became refugees. Let's not continue victimizing victims.
People should be able to keep their valuables, no matter where the people came from or where they are going. If the valuable could be perceived as a threat or if it is an illegal item in the new country, that is a different story completely. People take valuables with them because these items have value to them. Let them keep their things.
These refugees left behind so much, and anything they have will be something they will likely use to buy food and other things. If you want to account for it and then make them pay taxes when they sell it that is a different thing, but just taking valuables away makes it worse.
Not only is seizing the valuables of refugees legally problematic, it is morally problematic as well. These are people, including women and children, who have already suffered in unimaginable ways. Taking from them what little they were able to escape their home countries with only acts to add insult to injury.