You want to use the vector pen tool.
I searched for "fireworks tutorial pen tool" and found a couple of tutorials. One's long and in-depth, one's short.
Here's the short one: http://www.tutorialhero.com/tutorial-36176-vector_pen_tool.php
Here's the long one: http://www.communitymx.com/content/article.cfm?page=1&cid=A15CFD250F9D01EF
If you also need to have something for the glow, you may need to produce two lines (or duplicate the line once you've drawn it), and then use a filter on the one that is lower in the layer stack. Hmm...maybe duplicate it twice and apply the motion blur filter, once in each direction. Something like that, anyway.
If you draw a grid and want it to fade at the edges, similar to that shown in your image, group the grid, draw a circle/ellipse and put a gradient from white in the center to black at the edges. Select the grid group and the elipse and then Modify > Mask > Group as Mask. Where your ellipse is white, your grid will be unchanged. Where it's black, the grid will become fully transparent. Grey in the ellipse will set the opacity proportionally.