Korean Barbecued Fish

1 T olive oil
2 cloves garlic, minced
2 teaspoons minced serrano chilies
1/3 c soy sauce
1/4 c packed brown sugar
2 T water
3 T unseasoned rice vinegar
1 T sesame oil
3-8 fresh fish fillets (tilapia, flounder, sole, mahi mahi, etc.)
olive oil-flavored cooking spray or olive oil for brushing
salt and pepper

Heat olive oil in a small saucepan. Add garlic and chilies, and sauté about 3 minutes over medium heat. Add soy sauce, brown sugar, water, and rice vinegar, and bring to a boil, stirring. Reduce heat and simmer 5 minutes. Remove from heat and whisk in the sesame oil. Spray fish fillets with olive oil spray or brush with olive oil. Sprinkle lightly with salt and pepper. Baste with sauce and put on heated grill. Baste with more sauce during cooking.