There are maven plugins in existence that will auto-generate POM files from eclipse plugins. There are other example questions about that, How to create the pom.xml for a java project with Eclipse?
You can still use some existing ant scripts if you have to, using the maven-antrun-plugin artifact or the tycho-eclipserun-plugin artifact.
The target platform is created by filling in the repositories section with repos that have a layout of p2 (so they can be consumed by tycho).
Tycho is a good place to get started.