1 tsp. freshly ground Zen’s Chantaburi Black pepper
1 small yellow onion, thinly sliced, plus 1/3 cup finely chopped
2 1⁄2 lb. bone-in, skin-on chicken thighs (breasts work well too)
1 cup fresh lemon juice
1 cup thinly sliced scallions
2 1⁄2 tsp. Zen’s Roasted Thai Chili flakes
2 1⁄2 cups jasmine rice
2 tbsp. ground annatto (achiote) seeds. Or you can make the red achiote water by soaking the seeds and vigorously rubbing the seeds together to make a deep red-orange water for the rice.
To make the marinade, combine 2 cups soy sauce, vinegar, pepper, sliced onion, and 1 cup water in a large bowl; add chicken and cover bowl with plastic wrap. Refrigerate for at least 8 hours or overnight to marinate (the longer the better). Save the marinade to dip the chicken in while grilling.
Meanwhile, make the dipping sauce: Stir together remaining soy sauce and chopped onion with lemon juice, scallions, chili flakes, and 1⁄2 cup water; set aside.
To make the red rice, combine rice, annatto, and 5 cups water in a 4-qt. saucepan over medium-high heat; reduce heat to medium-low and cook, covered, until rice is tender, about 10 to 12 minutes. Remove from the heat and keep rice warm.
Build a medium-hot fire in a charcoal grill or heat a gas grill to medium-high. (Alternatively, heat a cast-iron grill pan over medium-high heat.) Cook chicken, turning, until browned, about 8 minutes. Before turning, remove and dip the chicken pieces in the leftover marinade. Serve with rice and dipping sauce, on the side.