If there's one thing I dislike more than dicing onions, it has to be dicing tomatoes. Slimy and juicy, dicing fresh tomatoes is probably one of the messiest jobs in the kitchen. Tomatoes are a finicky vegetable (fruit) especially with their outer skin making it seemingly impossible to cut with a chef's knife. However to every problem there is a solution-and this one involves a bit of knife skills and very sharp knife.
First things first, get your wooden cutting board set up and ready to go. If your board seems a bit wobbly, place a piece of wet paper towel under your board or even a piece of non-slip pad. The board shouldn't wiggle a bit.
Next it's onto the most important tool you have in the kitchen: a knife! While using a super sharp chef's knife is always the way to go, I find that a serrated knife works perfectly for cutting through the flesh and skin of fresh Roma tomatoes.
If needed, remove the tomato stem and cut the tomato stem. Using your knife, cut the tomato in half, then place the flat side of the tomato face down on the cutting board. Make horizontal slices through the tomato, parallel to your cutting board, making sure not to go entirely through the tomato. This is crucial for you to keep the tomato together.
Once the tomato is in slices, make vertical downward cuts through the tomato, almost as if you were slicing an onion. Once the tomato slices are made, cut across the tomato, creating diced tomatoes fit for our cucumber pico de gallo or even a tomato sauce.