There isn't a line tool, but there is a work around.
1. With the rectangle selection tool, you can draw a think long rectangle, like a line.
2. Then you can go to & and the Fill and Stroke tool.
3. Select the type, and make sure it is selected to Fill, and the color of your choice.
4. Below you can see the line drawn with the above method shown, and above it (the blue line) is just me using the spray can to draw a line.
I hope that helps. Please let me know if you have any questions,