Hello,
If you sell your RSU's that vested a month ago, and if you sell it at a higher price than the fair market value of the stock on the date of vestind, they will be taxed as a short term capital gain. A short term capital gain is taxed at ordinary income rates. If you wait and sell the stock more than a year later , they will be taxed at the more favorable capital gains rate.
California taxes RSU's at the mandatory tax rate of 10.23 %
I have included a link with more information on reporting sales of RSU's on your tax return:
https://turbotax.intuit.com/tax-tips/investments-and-taxes/how-to-report-rsus-or-stock-grants-on-your-tax-return/L55yZieu0