{WHOLE30 + VEGAN + GLUTEN FREE + NUT FREE}
In a small bowl of glass jar combine the red wine vinegar, water, and salt. Stir until salt is dissolved. Add the diced onion and stir so that it is mostly submerged.
Add paprika, cumin, chili flakes (if using), salt, and pepper. Cook for another minute or so, stirring frequently, until spices are aromatic.