Recipe from "Salsas That Cook"
Puree the salsa in a blender and press through a medium mesh strainer into a bowl. Heat the olive oil in a large skillet (I prefer a 12-inch non-stick skillet) over medium. Add the salsa and cook, stirring frequently, until reduced to the consistency of tomato paste (it should have reduced enough for the oil to have risen, leaving a sheen on the surface), 3 or 4 minutes. Remove from the heat and stir in the vinegar. Taste and season with honey and salt—it should taste slightly salty and have a hint of sweetness.
Stir the shrimp into the cooked salsa (there should be just enough to coat everything lightly) and return the pan to the medium heat. Cook, stirring
constantly, until the shrimp are just barely cooked through (cut open a
shrimp to see that it has turned from translucent to opaque white), about 3 minutes.
Scoop onto a platter and let cool to room temperature. In a small strainer, rinse the sliced onion under cold water and shake until nearly dry. Sprinkle over the shrimp along with the cilantro leaves, and the dish is ready to serve.