2 to 3 medium fresh tomatoes (1 to 1 1/2 pounds), stems removed
1/2 medium red onion
2 serrano or 1 jalapeño pepper, stems, ribs, and seeds removed (less or more to taste)
Juice of 1 lime
1/2 cup chopped cilantro
Kosher salt and freshly ground black pepper to taste
1 pinch dried oregano (crumble...