Pat chicken thighs completely dry with paper towels. Season both sides evenly with salt and pepper.
In a small bowl, combine gochujang, soy sauce, honey, rice vinegar, sesame oil, minced garlic, and grated ginger. Stir until smooth.
Heat 2 tbsp vegetable oil in a large skillet over medium-high heat. Carefully place thighs smooth side down and cook undisturbed for 5-6 minutes until deeply browned. Flip and cook another 4-5 minutes until just cooked through (internal temp 165°F/74°C).
Reduce heat to low. Pour the glaze over the chicken, letting it bubble for 1-2 minutes. Flip thighs to coat, then let the sauce reduce until thick and sticky, about 1 more minute. Remove from heat.
Transfer chicken to a cutting board, rest 3 minutes. Slice against the grain into strips. Drizzle any remaining pan glaze over the top, garnish with sesame seeds and green onions.