Shrimp Prep : Pat the shrimp very dry with paper towels so they sear quickly and don’t purge excess liquid.
Make the Picada : In a small bowl, combine the almonds, micro-planed garlic, lemon zest, and a pinch of Aleppo pepper if using. Stir in 2 tablespoons of the chopped parsley. Set aside.
Garlic-Paprika Oil : Add the olive oil to a large skillet over medium heat. Add the sliced garlic and smoked paprika (plus Aleppo if using). Cook 3–4 minutes, swirling occasionally, until the garlic turns pale golden and aromatic. Do not brown.
Flash-Cook the Shrimp : Add the finely chopped garlic to the skillet, then immediately add the shrimp in a single layer. Raise heat to medium-high. Toss and stir constantly for 2–3 minutes until the shrimp are just opaque with barely rosy centers.
Brighten and Season : Take the skillet off the heat. Add the sherry vinegar and lemon zest and toss to coat. Sprinkle in the fine sea salt and half of the remaining parsley and fold through. Taste and adjust acidity or heat to preference.
Toast and Serve : Toast the bread slices until crisp at the edges and still tender in the middle. Arrange the shrimp with their glossy garlic-paprika oil in a shallow bowl or small skillet. Shower with the almond–parsley picada and the remaining chopped parsley. Serve immediately with the crostini for dipping.