We construct a two-dimensional axisymmetric mean-field particle simulation scheme that solves the equations of relativistic scalar gravitation coupled to collisionless matter. Although scalar gravitation theory disagrees with experiment, it is useful as a testing ground for numerical methods used to solve the equations of general relativity, particularly in the generation of gravitational waves. We discuss methods for extracting the gravitational wave amplitude from the field variables, as well as methods for imposing an accurate outgoing-wave boundary condition on the scalar field at a finite radius. We find that for continuous matter distributions, our code is able to calculate smooth and accurate gravitational wave forms, despite the stochastic representation of the matter source terms caused by sampling with a finite number of particles. A similar scheme should provide accurate wave forms in general relativity, provided sufficient computer resources are used.