What is a kickboard?
A toe kick or kickboard (in the kitchen cabinetry sense) is a fascia that fits across the recess at the bottom of a floor-mounted base cabinet; these serve to conceal the plinths / supports of cabinet leg systems. Kickboards shouldn't bear any load, but should be fixed to load-bearing plinths or legs of the floor cabinets.
The purpose of kickboards is to enclose the areas underneath the cabinet - both for sanitary and aesthetic reasons. Kickboards give a finished look at the base of your kitchen cabinets, and it's not unusual for people to use a different material or trim to differentiate their kickboards from the rest of their cabinetry (stainless steel, for example).
Doing away with kickboards altogether may make your kitchen look more barren, although at the same time it can help to create the impression that your kitchen is more spacious. Kitchens without kickboards can look fantastic if they're designed with this in mind.
If you are planning to do without kickboards, you'll need to use specially finished legs (rather than the basic plastic supports that are mostly used these days). Likewise, you'll have to think carefully about what sort of floor you plan on using in your kitchen. It will need to be completely finished, and should ideally be a sturdy, long-lasting option like floorboards. If you opt for floating floor or vinyl, there's a fair chance your cabinets will need to be moved to reinstall the floor further down the track.
How are kickboards constructed?
Kickboard heights range from between 100mm to 200mm high. Common height tends to split the difference at 150mm. The nominal recess of the kickboard is 50mm from the front edge of the floor cabinet, or 70mm to the face of the door or drawer.
If the kickboard has exposed edges, these can be fixed using a waterproofing agent to prevent moisture from entering, or constructed using a moisture-resistant board.