Shape creation on uvias\pins

I don't know what layer you want it on, but you can use the Manufacture -> Create Bond Finger Soldermask command (it also allows you to select vias -- if you need pins, go into your user preferences and set the "icp_soldermask_allow_pins" option. Might need to restart the tool after that, can't recall offhand). This only allows you to create shapes on the soldermask top or bottom layer, but you can copy that shape to whatever layer and net you want pretty easily. Just make sure you set the clearances to 0.0 so that it creates a convex hull without any expansion around the via pads.

As to the conversion of clines into a shape, that exists, too, if you're running the latest version of 16.6. Set the "icp_cline_to_shape_beta" env var under the user preferences and restart the tool, I believe. It'll add a menu item under the Tool -> Convert menu for the Cline/Line to Shape tool. Pick the cline and it'll turn it into a shape for you. I think that one allows you to choose the class and subclass for the shape to go on, since it's a general conversion tool and not specifically a soldermask creation tool. If you have a bunch of them to do, this might be the quicker option, since it lets you do window selection for the items to convert, and you can set min/max line widths to filter to.

Hope that helps,
- Tyler