Pat the sushi-grade tuna dry with paper towels. Remove any sinew or dark bits and trim into a neat rectangular block. Return to the refrigerator to keep chilled until just before slicing.

Slice

Using a very sharp knife, slice the tuna into 1/4-inch thick slices (or into small cubes if you prefer a diced crudo). Arrange slices flat on a chilled serving plate or individual plates, leaving small gaps between pieces so sauce will be visible.

Season lightly

Sprinkle the plated tuna lightly with 1 teaspoon fine sea salt and 1/2 teaspoon freshly ground black pepper, distributing evenly.

Finish with oil

Just before serving, drizzle 2 tablespoons extra-virgin olive oil evenly over the tuna slices.

Salsa Verde

Prepare herbs and aromatics

Wash and thoroughly dry the parsley and basil. Remove large stems and roughly chop leaves. Mince 1 clove garlic finely. If using anchovy, finely chop the fillet. Rinse and drain capers to remove excess brine. Finely chop cornichons.

Combine and mash

In a medium bowl, place the chopped parsley, basil, capers, cornichons, anchovy (if using), and minced garlic. Add 1 teaspoon lemon zest and 2 tablespoons fresh lemon juice. Using the back of a spoon or a small pestle, lightly mash the mixture to release juices and combine textures — you want a slightly coarse, spoonable salsa rather than a smooth purée.

Emulsify

While stirring, slowly whisk in 4 tablespoons extra-virgin olive oil to form an emulsion. Add 1 teaspoon red wine vinegar, 1/4 teaspoon black pepper, and 1/2 teaspoon flaky salt. Taste and adjust acidity or salt — add up to 1 teaspoon more lemon juice if you want a brighter edge, or a pinch more salt.

Rest

Let the salsa verde sit at room temperature for 10 minutes to allow flavors to meld. If making ahead, cover and refrigerate for up to 4 hours and bring back to room temperature before serving.

Assembly & Garnish

Spoon salsa onto tuna

Using a spoon, dollop or smear small teaspoons of the salsa verde between and over the tuna slices. Aim for roughly 1 to 1.5 tablespoons of salsa per ounce of tuna overall (adjust to taste) so each bite has a balance of fish and sauce.

Add garnishes

Scatter microgreens or baby arugula lightly over the plate. Tuck thin radish slices among the tuna for crunch and color. Sprinkle 1/4 teaspoon cracked black pepper and, if desired, a few pinches of flaky sea salt over the finished dish.

Serve

Serve immediately with lemon wedges on the side for diners who want extra brightness. Recommend serving chilled on a cool plate and eating within 15 minutes for best texture and flavor.