You can to the sprite collection data object. Check tk2dRuntimeSpriteCollection.cs for how to create sprites from rects in a texture. You can use that to manipulate your runtime sprite collection in any way. Just remember - the sprite IDs should never change. So if you're adding one, increase the size of the array by all means, but when deleting the first out of the full array, don't shift everything up, just clear the first entry.