Pat the chicken dry with paper towels and season all over with salt and pepper. Zest one lime and set aside; juice both limes into a small bowl, keeping zest and juice separate for now.

Heat coconut oil in a large skillet over medium-high heat until shimmering. Add chicken in a single layer and cook undisturbed for 4-5 minutes until golden brown. Flip and cook 3-4 minutes more until just cooked through. Transfer to a plate; the chicken will finish cooking in the sauce.

Reduce heat to medium. Add garlic and ginger to the skillet and saute for 30 seconds until fragrant, scraping up any browned bits. Pour in coconut milk, fish sauce, brown sugar, half the lime juice, and red pepper flakes if using. Stir to combine and bring to a gentle simmer.

Return chicken and any accumulated juices to the skillet. Simmer for 8-10 minutes, stirring occasionally, until the sauce thickens enough to coat the back of a spoon and chicken reaches 165F internally. Remove from heat and stir in the reserved lime zest and remaining lime juice to taste.

Taste and adjust seasoning - add more lime juice for brightness or a pinch more sugar to balance. Serve over jasmine rice with chopped cilantro scattered on top.