Pat chicken dry, season with salt and pepper. Heat oil in a large skillet over medium-high heat.
Sear thighs skin-side down until golden, 6–8 minutes, then flip and cook 4 minutes more. Remove to a plate.
Add garlic and ginger to skillet, cook 30 seconds, then stir in soy sauce, honey, and vinegar.
Return chicken and add pineapple chunks. Reduce heat, cover, and simmer 12–15 minutes until chicken reaches 165°F.
Remove chicken, skim fat if needed, and stir cornstarch slurry into sauce to thicken. Return chicken to coat and garnish.