In a bowl or jar, whisk together the coconut aminos, lime juice, garlic, chili powder, smoked paprika, cumin, red pepper flakes, salt, and pepper.
Place the chicken thighs into a resealable bag or shallow dish and pour the marinade over the chicken. Coat evenly and refrigerate for at least 30 minutes or up to 24 hours.
Prepare the mango cucumber salsa and refrigerate until ready to serve.
Rinse the rice under cold water until the water runs clear.
For the Instant Pot, combine rice, coconut milk, and salt. Cook on High Pressure for 3 minutes, then allow a natural pressure release for 10–15 minutes before releasing any remaining pressure.
For the stovetop, combine rice, coconut milk, and salt in a saucepan. Bring to a boil, reduce to low, cover, and simmer for 15–20 minutes until tender.
Heat a grill to medium-high heat (400–450°F / 204–232°C).
Grill the marinated chicken over direct heat for 6–8 minutes. Flip, move to indirect heat, and cook another 5–10 minutes until the internal temperature reaches 165°F (74°C).
Let the chicken rest for 5 minutes before slicing.
Assemble the Summer Grilled Chicken and Rice Bowl by dividing coconut rice, romaine lettuce, grilled chicken, mango cucumber salsa, and avocado among serving bowls.
Finish with fresh cilantro and a squeeze of lime juice before serving.