I think you are stuck with having to loop through the points to find the triangles you want to make faces from. You might be interested in the PolygonMesh class. It looks like it might be able to handle the mesh creation faster than just adding the faces directly.
http://code.google.com/apis/sketchup/docs/ourdoc/polygonmesh.html
@unknownuser said:
The PolygonMesh class contains methods to create polygon mesh structures. This is useful if you need to write a custom importer/exporter in Ruby that works at the level of triangulated polygons. For example, you can determine the triangles that make up a 15-sided SketchUp face by using this class, or write a SketchupImporter that reads a data file, creates a mesh from it, and draws faces based on the mesh.
IT also mentions in al old version of the API that you can pre-specify the amount of points and faces that are going to be added to the mesh to speed up the creation process.
Glad you can work out the delauney bit, I'm sure you'll get the SketchUp API under control in no time,
Chris