Wash the tomatoes. On a cutting board, cut the tomatoes in ½, from the core to the tip. Remember to hold the hand holding the tomato like a claw. Cut each half into 1 cm wide slices, then cut the slices into small squares. Place in a small bowl.
Cut the onion in ½, from the hairy end to the tip then ½ again. Remove the skin. Cut 1/4 onion into 1 cm wide slices. Cut each slice into cm wide strips. Add to the tomatoes.
Pick the leaves off of the cilantro, then tear the leaves up and add to the tomatoes.
Peel the skin off the garlic and press through a garlic press or grate with a microplane. Add to the tomato mixture.
Juice the ½ lime with a juicer or reamer and add to the tomato mixture.
Add the salt to the mixture and mix together with a spoon.
Let sit for about 15 minutes before eating.
Add chili flakes or hot sauce to the salsa if you like things spicy.
You can also add black beans or corn kernels, for different flavours.