As a dual citizen living outside the U.S., do I still have to file U.S. taxes?

Yes. The United States is one of very few countries that taxes based on citizenship rather than residence, so a U.S. dual citizen must file a U.S. tax return reporting worldwide income no matter where they live or whether they have ever worked in the States. You may owe little or nothing after applying the Foreign Earned Income Exclusion or Foreign Tax Credit, but the filing obligation itself remains, along with FBAR and possibly Form 8938. Many so-called accidental Americans, people who gained citizenship by birth or parentage but live abroad, are unaware of this. Penalties for non-filing of information returns can be severe. The IRS offers Streamlined Foreign Offshore Procedures for those who need to catch up in good faith. See irs.gov and consider professional help given the complexity.