In skillet, on med-high heat, saute meat and onions until meat is in small bits and onion is transparent about 6 minutes.
Add garlic and continue to saute until garlic is fragrant, a minute or two.
Pour in the first half of the water, scrape the pan, and add the ketchup, Worcestershire sauce, brown sugar, salt, and pepper. Simmer for 3 min on med-high heat.
Add the additional water, turn heat down to medium and simmer for 12-15 minutes, or until thickened. Stir often.
Stir in the sriracha and vinegar. Let stand a couple of minutes. Serve.