A wide open aperture will have a small "f-number". f/2, for example, is much bigger / wider open than f/8.
('f' means 'focal length', so f/2 means 'focal length divided by 2', or 'the aperture is half the focal length'. 'f/8' means 'the aperture is only 1/8th of the focal length, which is much smaller than one half').
A wide open aperture will produce a shallow depth of field - so if you focus on your subject and use a wide open aperture, a narrow field should be in focus at the subject. Both the foreground and background should be out of focus.
The exact depth of field that is in focus is proportional to your distance from the subject. Just how "out of focus" the background and foreground are depends also on their distance from the subject, so as Duncan suggested - if you can position your subject as far from the foreground that you want blurred, as possible, that will maximise the effect.
Bokeh refers to the nature of the blurring. For example, when pinpoint highlight (such as light sources) are out of focus, does the blurring show a particular shape? Or is it round? etc. It does not necessarily refer to how far out of focus those points are. It refers more to the nature of the blurring. Therefore I think what you mean to ask is how to minimise the amount of subject that is in focus (ie. achieve a shallow depth of field). Areas that are out of focus (including both foreground and background) will exhibit bokeh - but that's irrelevant to the question of how to get foreground out of focus.