In medium bowl, whisk together aji paste, lime juice, lemon juice, oil, minced cilantro, grated ginger, and smashed garlic clove. You also can place everything in the blender.
Chill the sauce thoroughly before using. The sauce may be also made up to five days ahead of time to this point. Store refrigerated.
When ready to serve, thinly slice the fish on a slight bias against the grain. Shave the slices as thin as you can manage; no more than ¼-inch thick (preferably even thinner).
Lay the fish in a single layer, barely overlapping, onto a chilled serving plate. Pour enough tiradito sauce over the fish slices to thoroughly coat; you might not use all the sauce, use your judgment. Let the platter sit a few moments before you serve, but no more than 15 minutes.
Garnish with chili slice, cilantro sprig and sea salt. Serve immediately.