Shen carries a pair of blades, and uses both at once for his Ki Strike (and Vorpal Blade; he throws one and uses the other in melee combat). But if it is not enough...
Dual-wielding is having another sword or a parrying dagger instead of a shield. or carrying two swords instead of a two-handed sword. First, you need concepts of some skills which are best with dual-wielding (look stronger, and more BADASS! not always have to be practical).
For example, in real-life swordplay, you can use the off-hand short-sword for a secondary attack, when the primary attack is blocked or you get too close to an enemy to use the longer sword. You can also parry with it, which is not really practical compared to a shield, but adds a bit of badassery.