Warm up the avocado oil in a large skillet over medium heat until shimmering.

Add the boneless chicken thighs to the skillet and cook until they are golden brown, about 6-8 minutes per side.

Stir in the finely diced onion, minced garlic, and fresh ginger. Sauté until fragrant and onions are translucent, approximately 3-4 minutes.

Mix in the red Thai curry paste and kaffir lime leaves, cooking for an additional 2-3 minutes.

Toss in the red bell pepper, full-fat coconut milk, diced mango, chicken stock, and roughly chopped spinach. Stir to combine.

Allow the mixture to simmer on low heat until the chicken is fully cooked and the spinach is wilted, about 15 minutes.

Stir in the freshly squeezed lime juice and fish sauce, taste and season with sea salt as desired.