Step 1: Prepare your ingredients. Wash and roughly chop the tomatoes. Peel and roughly chop the onion and garlic cloves. Wash the jalapeño(s) and remove the stem. For less heat, slice the jalapeño in half lengthwise and scrape out the seeds and white membrane with a spoon. For more heat, leave some or all of the seeds.
Step 2: Add all vegetables to a food processor. Place the chopped tomatoes, onion, garlic, prepared jalapeño(s), and fresh cilantro into the bowl of a food processor.
Step 3: Pulse to desired consistency. Secure the lid on the food processor and pulse in short bursts until the salsa reaches your preferred consistency. For a chunky salsa, pulse fewer times. For a smoother salsa, pulse more, but be careful not to over-process into a watery puree. Scrape down the sides of the bowl as needed.
Step 4: Season the salsa. Transfer the pulsed salsa to a medium-sized bowl. Stir in the fresh lime juice, sea salt, and black pepper. Taste the salsa and adjust the seasonings as needed. You may want to add more salt or lime juice. If your tomatoes are a bit tart, a small pinch of sugar can help balance the flavors.
Step 5: Chill to meld flavors. Cover the bowl and refrigerate the salsa for at least 30 minutes. Chilling allows the flavors to meld and deepen, resulting in a much more delicious final product. For best results, chill for 1-2 hours.
Step 6: Serve and enjoy. Give the salsa a final stir before serving with tortilla chips, as a topping for tacos, grilled meats, eggs, or anything else that could use a burst of fresh flavor. Store any leftover salsa in an airtight container in the refrigerator for up to 5-7 days.