I'm assuming the might mouse has a right click, but I rarely use one so don't know the product. Try clicking on the right side of it......
If you're not using a mouse with a right click (and a scroll wheel), you're missing out on a lot of editing power, IMHO.
If you have a right click mouse, either hit the escape key and right click on tool of choice or left click on the right click menu and select tool of choice.
Lastly, you can assign a dedicated key command in the key command window. Type in scissors and it will show up.