Here is an easy step by step way to dice a tomato!
1. Start with a tomato of your choice and a sharp knife
2. Cut tomato in half
3. Remove core
4. Slice all the way through with knife flat and parallel to the cutting board, MAKE SURE ALL FINGERS STAY ABOVE THE KNIFE!
5. Slice tomato into strips about the same width as the previous slices
6. Turn tomato and slice again about the same width as the previous cuts
7. Now that you have diced half of the tomato, repeat with the other half!
Please be cautious when making cuts, make sure your fingers are clear of the blade and are bent back. Also the sharper your knife the easier it will go through your tomato so make sure your knives are well sharpened.