Adjust with what you have on hand— use red onion in place of the shallot, jalapeño in place of the Serrano, other herbs in place of the cilantro, etc. 

Simple Orange Salsa

Makes 1 to 2 cups

• 2 to 3oranges, peeled, segments cut from pith
• 1small shallot, thinly sliced
• 1small Serrano pepper, seeds removed, finely diced
• Small amount of cilantro, coarsely chopped
• Salt, to taste
• 1 to 2tablespoons olive oil

1. Place the oranges in a medium bowl. Squeeze rinds and remaining membranes into the bowl to extract all of the juice. Add the shallots, pepper, cilantro, pinch salt and 1 tablespoon olive oil. Taste. Adjust as needed with more salt or oil. If you need more acidity, you can add a splash of vinegar or a squeeze of lemon or lime juice.

https://food52.com/recipes/67905-simple-orange-salsa