I'm not familiar with a solution to your first problem, other than learning the standard. It's not clear to me any particular problems you're having with it other than it's not to your liking, not to say that's not a good reason to ask the question!
With that in mind, in order to delete everything before a certain spot in a text file, you can most likely hold Shift and press the Home button. That should select all of the text, so you can now press Backspace, or Delete, as you prefer, to remove the text. The opposite can be done with the End key.
As you pointed out in the comments, most text manipulation shorcuts are bound to Ctrl and Shift, such as copy and paste, while Alt and Super are reserved for other functions. This is a major difference between Meta Characters and Control Characters.