Heat a wok or large skillet over high heat until a drop of water evaporates immediately. Swirl in the oil, then add the garlic. Stir-fry for a minute or so, until fragrant and just starting to brown.

Add the bell peppers and a pinch of salt and stir-fry until well seared, 2-3 minutes. Add the shrimp, remaining salt, and sugar and continue stir-frying until the shrimp are just barely cooked (see Tips).

Transfer to a serving plate and sprinkle with white pepper, scallions, and sesame oil to taste. Serve alongside a steaming bowl of rice.