Prep: Rinse the rice, juice the citrus, finely mince the garlic, and trim the chicken thighs.
Make the mojo marinade by whisking together citrus juice, garlic, avocado oil, oregano, salt, and any optional ingredients; set aside 2–3 tbsp of the mojo before adding the chicken.
Season the chicken thighs with cumin and salt, then pour the remaining mojo over them and let them marinate while you cook the rice.
Bring 2 cups of water, ½ tsp salt, and 1 tbsp oil to a boil, add rinsed rice, and cook uncovered until the water reduces and bubbles appear.
Reduce heat, leave the rice uncovered for 2–3 minutes, then cover and steam on low for 5–7 minutes until fluffy; remove from heat and let sit.
Grill the chicken for 5–6 minutes per side over medium-high heat until fully cooked and lightly charred; let rest before slicing.
Build each bowl with rice, sliced chicken, avocado, red onion, cilantro, and sweet plantains or plantain chips.
Drizzle with the reserved mojo and serve with lime wedges.