Heat the oil in a large skillet over medium heat. Add the onions and cook, stirring occasionally until softened but not brown, about 4 minutes. Add the garlic, oregano, cumin, and peppercorns and cook, stirring for 1 minute. Add the jalapenos, carrots, cauliflower, and bay leaf and cook for another minute. Add the vinegar, water, sugar, and salt and bring to a boil. Reduce heat and let simmer for 10 minutes.
Using a slotted spoon, spoon the vegetables into mason jars (about 3 pint jars or 2 quart jars). Spoon the brine over the vegetables. Let cool. Refrigerate for at least 3 hours before serving. Will keep in the fridge for about 1 month.