Core and seed the Roma tomatoes (seeds optional if you want a less watery salsa). Finely dice so that you end up with about 1.5 cups of diced tomato. If tomatoes are very juicy, drain for 5–10 minutes in a sieve to remove excess liquid.

Dice aromatics

Finely dice the red onion and place in a small bowl. Mince the garlic and the jalapeño (remove seeds for milder heat). Add both to the bowl with the onion.

Combine base ingredients

In a medium mixing bowl combine the diced tomatoes, red onion mixture, and the chopped cilantro. Add the minced garlic and jalapeño to the bowl.

Season and balance

Stir in the lime juice, olive oil, sea salt, black pepper, and ground cumin if using. Mix gently until everything is evenly combined. Taste and adjust seasoning — add more salt or lime juice if needed.

Rest for flavor meld

Cover the bowl and refrigerate for at least 30 minutes to allow flavors to marry. For best flavor, rest 1–2 hours. If you prefer a room-temperature salsa, let it sit at room temperature for 15–20 minutes before serving.

Final adjustment

After resting, taste again and adjust salt, lime, or jalapeño heat. Give a final stir and transfer to a serving jar or bowl until ready to serve.

Optional add-ins / garnish

If using avocado, dice it just before serving and gently fold into the salsa to avoid browning. If using mango or pineapple, fold in small diced pieces during the final adjustment step. Garnish with extra cilantro.