It is important to realize that shortcuts have to be taken when reading papers so that there is time left to get our other work done, including writing, conducting research, attending meetings, teaching, and grading papers.
This reminds me of a conversation I had not too long ago with a counselor about how I can take so many credits at school, at the time i was taking 18. You have to take the shortcuts where they are available. You can't be as thourough as you'd like, but you can be efficient.
I like to print out the paper and highlight the most relevant information, so on a quick rescan I can be reminded of the major points.
I also like to print stuff out and go through it. I retain the most information if I physically write stuff down. I think you see stuff differently in person than online.
Sometimes I start by skimming through to see how much might be relevant. If it is directly applicable to my current topic, I'll read the paper closely, apart from the introduction that is probably already familiar.
I think this is the key to efficient learning. You have to understand where the most important information is and save time by reading where you can get the most from.