1. You don't enter the intersection if you can't get out of the intersection. That means you don't enter to make a left turn if you have to sit in the intersection while you wait for oncoming traffic to clear, and end up turning on red. You wait at the stop line, and if you don't get to enter while the light is still green, you wait until the next one.
2. Where I live, you can turn left on a red, if it is the intersection of two one way streets.