You can't create a “level playing field” by imposing more big government restrictions, all you can do is further mess up the market mechanisms. The result of restricting imports from China will mean higher prices in the United States with no rise in income. The only institutions that gain are the government and American manufacturers. It doesn't help the Economy, production costs will rise, if the tariff applies to raw materials and intermediate goods. This puts further pressure on the price level and causes American production to decrease.
We need to quit strangling American business, not start strangling foreign business. If we really want to level the playing field we should consider lowering the corporate tax rate, and disbanding the EPA and OSHA. Getting rid of the minimum wage would help as well, I know that's extremely unpopular, but it would decrease unemployment.
Adding foreign workers is not going to count in the GDP numbers, or the jobs added numbers. If you want to make American companies less profitable so they have to lay off American workers go ahead and use the powers of our Leviathan government to make them stop, but you won't like the side effects. Oil is a great example everyone understand we can't just cut off the supply of foreign oil, without lifting restrictions on domestic production. The same logic applies here.