In a large bowl, combine the minced garlic, ground cumin, paprika, aji panca paste, white vinegar, vegetable oil, salt, and pepper.
Mix well to form a marinade.
Add the beef heart cubes to the bowl with the marinade.
Toss to ensure the meat is evenly coated with the marinade.
Cover and refrigerate for at least 4 hours, preferably overnight.
If using wooden skewers, soak them in water for about 30 minutes to prevent burning.
Thread the marinated beef heart cubes onto the skewers.
In a blender, combine the aji amarillo paste, vegetable oil, white vinegar, ground cumin, garlic powder, and salt.
Blend until smooth. Adjust seasoning to taste.
Preheat a grill or grill pan to medium-high heat.
Grill the skewers for about 5-7 minutes on each side, or until the meat is cooked to your desired level of doneness.
Brush the skewers with the prepared sauce during the last few minutes of grilling.
Enjoy your meal!