You can make your dices as big or as little as you want. I would suggest larger pieces for chili, soups or spaghetti sauce. Use smaller dices for pico de gallo and chicken salad (if you put onion in yours).
Place your hand on top of the onion to keep it from sliding all over the place. Run your knife through the onion parallel to the cutting board, stopping just before the core. I usually make about 4 slices from top to bottom.
Now make cuts perpendicular to the cutting board, remember to stop right before the core. You can see those little dices just waiting to be free!
Now turn your onion and cut your dices! Pretty easy huh?
These onions went into the pot to make my Spicy Red Pepper Marinara. Recipe coming soon!