1/2 medium white onion, finely chopped (generous 1/2 cup)
1 1/4 pounds ripe tomatoes, cut into 1/2-inch pieces (about 3 cups), or substitute drained canned tomatoes
3 to 4 medium serrano peppers, or 2 to 3 small green jalapeño peppers, finely chopped
1/2 cup loosely packed chopped fresh cilantro
1 teaspoon kosher salt
1/4 teaspoon sugar
5 tablespoons fresh lime juice
1 1/2 tablespoons vegetable oil
Depending on how much water is in the tomatoes, you may want to drain some of the excess liquid from the salsa before serving. May be stored in the refrigerator for up to 1 week.