This mod simply removes rocks from the map as chunks are generated.
By default, it will remove only rocks, but if you want more features, you can edit config.lua. Available options are:
removeTrees: remove all trees (living and dead) from the map.removeDecorative: remove all decorative doodads (small rocks, shrubs, etc.)layConcrete: Fill the whole map (excluding water) with concrete on generation.
This lets you play in a more open sandbox type mode without having to worry about clearing terrain first.