Combine black vinegar and sherry vinegar in a bowl.

Add thinly sliced shallots to the vinegar mixture and let sit for 1 hour, tossing occasionally.

Drain shallots and pat dry.

Cut slab bacon into 1x1/4-inch pieces.

Cook bacon in a skillet over medium heat until fat is rendered and bacon begins to brown (5-7 minutes).

Transfer bacon to paper towels.

Pour off bacon fat and reserve.

Wipe out skillet.

Fit a pot with a deep-fry thermometer and add oil to come 2 inches up the sides.

Heat oil over medium-high until thermometer registers 300°F.

Whisk together flour and cornmeal in a shallow bowl.

Dredge shallots in the flour mixture, shaking off excess.

Fry shallots, tossing occasionally, until golden and crisp (about 3 minutes).

Transfer shallots to paper towels and season with salt.

Heat the reserved skillet over medium-high heat.

Swirl 1 tablespoon of vegetable oil in the pan to coat.

Add thinly sliced asparagus, season with salt, and cook, tossing, until almost cooked through (about 1 minute).

Add cooked bacon and 1 tablespoon of water; cook, tossing, until asparagus is cooked through (about 30 seconds).

Add white soy sauce and toss to coat.

Serve topped with crispy shallots.