Core and roughly chop the tomatoes into 1/2–3/4-inch pieces. If tomatoes are very juicy and you want a thicker salsa, scoop out and discard about 1/4 cup of the seeds/juice before chopping.

Prep onion and jalapeño

Peel and finely dice the onion to yield about 1 cup. Halve the jalapeños lengthwise, remove seeds and membranes for milder heat (reserve some seeds if you want more heat), then finely mince. If you prefer a smoother texture, remove the ribs as well.

Combine ingredients

In a medium bowl, combine the chopped tomatoes, diced onion, minced jalapeño, and the drained canned green chiles. Stir to mix evenly.

Add seasoning and herbs

Fold in the chopped cilantro, lime juice, kosher salt, black pepper, and optional cumin and olive oil. Taste and adjust salt and lime — add more lime juice 1/2 tablespoon at a time if you want brighter acidity, or more salt 1/4 teaspoon at a time to balance.

Rest and meld flavors

Cover the bowl and refrigerate for at least 20–30 minutes to allow flavors to marry. For best flavor, chill 1–2 hours. If serving immediately, let sit at room temperature 10 minutes and re-taste for seasoning.

Final adjustment and serve

Stir the salsa before serving. If it seems watery, drain off excess liquid or gently press with a slotted spoon. Serve chilled or room temperature with tortilla chips, tacos, or as a condiment.