Spread the lentils on to a sheet pan or large plate and sort through to remove any debris, shriveled lentils, or small rocks. Transfer lentils to a mesh strainer and rinse thoroughly.
Transfer lentils to a 4-quart pot along with the salt, onion, garlic, bay leaf, and salt pork. Add enough water to cover by an inch (about 4 cups), bring to a boil over medium-high heat, then reduce to low, cover, and simmer until lentils are just tender, 20 minutes.
Carefully move the cooked lentils to the mesh strainer to drain and cool, discarding the aromatics and salt pork.
Cook the bacon using our Oven Roasted Bacon method, reserving 2 tablespoons of the rendered fat. Crumble the cooked bacon and set aside. Whisk together the rice wine vinegar, shallot, Dijon mustard, salt, pepper, parsley, and thyme in a large bowl, then drizzle in the reserved bacon fat, whisking to emulsify. Fold in the lentils and bacon and park at room temperature for at least 15 minutes to allow the flavors to meld before serving.