Roast serrano peppers on the grill or a gas burner until the skin has blistered all the way around. Alternatively, you can put the peppers on a sheet tray under the broiler until the skins have blistered. Once the peppers are cool enough to handle, use a paper towel to remove the skins, then finely chop the peppers. You can remove the seeds and rib if you want to reduce the heat.

In a medium bowl, combine the Greek yogurt and lemon juice. Season with salt. Add the tahini and mix to combine. As you mix, the sauce will start to thicken. Stir in smoked paprika, chili flakes, ground coriander, and the chopped serrano pepper. Adding a little at a time, use water to thin the sauce to your desired consistency. Adjust salt and lemon juice to taste. Set aside until ready to serve the crudo.

Cut the snapper fillet through the middle to create two pieces. Lay the snapper pieces skin-side down on the cutting board. Using a flexible knife if possible, insert your knife horizontally between the skin and the flesh. Gently glide your knife back and forth to remove the skin, leaving as little fish as possible behind. Repeat with the other piece. Slice the snapper into 1/8-inch wide pieces. Season with salt.

Arrange snapper slices on individual plates. Dress the snapper with lime juice and a few splashes of sweet white vinegar, if using. Spoon yogurt sauce over the fish and then top with cucumber and shallots. Sprinkle crudo with sesame seeds and Aleppo pepper. Lightly drizzle olive oil over the dish and then finish with basil leaves.