The first sentence sounds natural. It is similar to: - It's about time I opened my eyes... - I need to face facts. - It's time to face reality. The 2nd sentence doesn't sound very natural because of "Something...". It would be more usual to say, e.g. "That was an eye opener", as presumably you would be referring to something specific.

Both seem natural to me. All of these are correct: 1 - "It is time that he open his eyes to the truth" 2 - "It was time that he open his eyes to the truth" 3 - "It is time that he opened his eyes to the truth" 4 - "It was time that he opened his eyes to the truth" #3 and #4 mean that he hasn't yet opened his eyes to the truth and that he should do so. #1 and #2 merely say that he should do so. I used "he" rather than "I" so you could see the subjunctive mood ("open", not "opens")