In a large pot or container, heat 8 liters of water to 136°F/58°C
Dab the pork tenderloin dry with paper towels.
In a small bowl, mix 1 teaspoon salt with the sugar.
Coat the pork tenderloin with 1 tablespoon olive oil, then sprinkle with the salt and sugar mixture on all sides.
Pack the seasoned tenderloin into a sous vide bag or zip-top bag. Submerge in the water bath and cook for 1 hour and 30 minutes.
Meanwhile, in a medium bowl, combine the remaining ½ teaspoon salt, ¼ cup olive oil, chives, parsley, garlic, onion, pepper, jalapeño and chive blossoms.
Remove the pork tenderloin from the bag and dry any excess moisture with paper towels. In a large skillet, melt the butter over high heat. Once it starts to foam, sear the tenderloin for 90 second on each side or until golden brown. Immediately remove the pork from the skillet and rest for 2 minutes.
Serve the pork with the herb oil and flaky salt on top.