For the Chicken:
3 medium cloves garlic, roughly chopped
4 teaspoons (15g) kosher salt
2 tablespoons ground cumin
2 tablespoons paprika
1 teaspoon freshly ground black pepper
2 tablespoons (30ml) white vinegar
2 tablespoons (30ml) vegetable or canola oil
4 boneless, skinless chicken breasts (5 to 7 ounces/140 to 200g each), cut into 8 cutlets
For the Sauce:
3 whole jalapeño chilies, roughly chopped (see note)
1 tablespoon (15ml) ají amarillo pepper paste (optional; see note)
1 cup (1 ounce) fresh cilantro leaves
2 medium cloves garlic
1/2 cup (120ml) mayonnaise
1/4 cup (60ml) sour cream
2 teaspoons (10ml) fresh juice from 1 lime
1 teaspoon (5ml) distilled white vinegar
1/4 cup (60ml) extra-virgin olive oil
Kosher salt and freshly ground black pepper
For the Chicken
In a large mortar and pestle, pound garlic and salt until a smooth, sticky paste forms. Add cumin, paprika, black pepper, and vinegar and grind them together to form a paste. Drizzle in vegetable oil while grinding (see note). Transfer chicken and marinade to a large bowl and massage with your hands until all the chicken is coated in the marinade. Set aside at room temperature while you make the sauce, or cover and place in the fridge up to overnight.
Place chicken directly over the hot side of the grill, cover, and cook, rotating the pieces occasionally (but not flipping them), until the chicken is almost completely cooked through and only a few pink spots remain on the top side, about 4 minutes. Flip chicken and cook on second side until just done, about 30 seconds. Transfer to a large plate.
For the Sauce
Combine jalapeños, ají amarillo (if using), cilantro, garlic, mayonnaise, sour cream, lime juice, and vinegar in the jar of a blender. Blend on high speed, scraping down as necessary, until smooth. With blender running, slowly drizzle in olive oil. Season to taste with salt and pepper. Sauce will be quite loose at this point, but will thicken as it sits. Transfer to a sealed container and refrigerate until ready to use.
Serve
On pita or flat bread with pickled onions, tomatoes, microgreens, chicken and sauce