Spicy Grilled Chicken

Name: Spicy Grilled Chicken
Cuisine: Asian, Korean
Ingredients: 2 pounds boneless chicken thigh (You can use chicken breast if you want); 2 to 3 tablespoons gochugaru (고추가루), Korean red chili pepper flakes (or to taste); 1 tablespoon sugar; 3 tablespoons soy sauce; 2 tablespoons rice wine or mirin (White wine is good too.); 2 tablespoons gochujang (고추장), Korean red chili pepper paste; 2 tablespoons honey or 3 tablespoons corn syrup or oligodang (올리고당); 2 tablespoons maesil chung, 매실청 (or 2 to 3 tablespoons pineapple juice or grated apple); 1 tablespoon sesame oil; 1/4 medium onion, grated (about 1/4 cup); 2 tablespoons minced garlic; 2 teaspoons grated ginger; 1/2 teaspoon salt; pepper to taste; 2 tablespoons chopped scallions; 1 teaspoon sesame seeds