Make the marinade. Combine the olive oil, jalapeño, cilantro, lime zest and juice, Worcestershire sauce, cumin, oregano, salt, and aji amarillo paste in a blender, then blend until it's smooth. Save 1/3 cup of marinade for later.
Spatchcock the chicken. Use the directions above to spatchcock the chicken. Make sure to separate the meat from the skin so the marinade can touch the meat directly.
Marinade the chicken. Put the chicken in a Ziplock bag, then pour the marinade over the chicken. Brush the marinade between the skin and meat on the breasts. Close the bag and release any extra air, then place the chicken in the fridge for 2-24 hours.
Grill the chicken. Heat the grill on medium high heat. Brush the grill with olive oil, then place the chicken on the grill. Discard the bag and used marinade. Brush the chicken every 10 minutes with the extra marinade that was set aside when it was made. Grill the chicken for about 45 minutes, until the internal temperature is 165 degrees.
Make the aji verde sauce. Combine the bunch of cilantro, mayonnaise, garlic, jalapeño, lime juice,salt, and aji amarillo paste in a bender and blend until smooth.
Serve. Cut the chicken along the bones to serve individual portions. Plate with the sauce, and mangia!