With only 3 User Interface Design job opportunities at the moment in Singapore, it might be worthwhile to check out job ads in similar areas of expertise. Subsections include most dominantly Design and Usability. Swot up on UX, UI and User Research to make sure you're the right fit for jobs like this.
On Jobspotting, you can find job ads for a wide variety of experience levels and apply filters to find the ones that are for you. With just one startup at the moment publishing jobs on Jobspotting, it's worth considering traditional companies too. Have you seen which other skills are in demand in this region?