Mince garlic, separate green onion whites and greens, and mince chilies if using.
Boil riblets in water with a pinch of salt and 1 tablespoon vinegar for 2 minutes. Rinse under cold water and drain.
Heat oil in a skillet with a pinch of cornstarch. Fry ribs until golden on all sides, then remove from skillet.
Add 3 tablespoons oil to skillet, fry garlic until pale gold. Reserve half for garnish.
Add green onion whites and minced chilies to remaining garlic oil. Add fish sauce, chili sauce, sugar, water, seasoning powder, and optional paprika. Bring to a gentle simmer.
Return fried ribs to skillet, cover and simmer on low until ribs are tender and glaze reduces. Stir frequently near the end. Add reserved garlic chips, toss once more, then turn off heat.
Move ribs to a serving plate, top with green onion greens and black pepper, and serve immediately.
See more recipe:
https://chinsu.com/blog/vietnamese-pan-fried-ribs-recipe