Chop the ripe tomatoes into small, even pieces and place them in a mixing bowl.
Add the finely diced red onion and chopped cilantro to the bowl with the tomatoes.
Juice the lime over the mixture, ensuring to catch any seeds, and stir gently to combine all the fresh ingredients.
Sprinkle in salt and black pepper, then fold everything together with a spoon until evenly mixed and the flavors meld.
Let the salsa rest for 5 minutes to allow the flavors to develop fully.
Give the salsa a final stir, then transfer to a serving dish. Serve immediately or refrigerate for up to two hours for a cooler, more refreshing flavor.