HEAT oil in large skillet or wok on medium-high heat. Add onion and garlic; stir fry 30 seconds. Add fish sauce, red chili paste and sugar; stir fry 2 to 3 minutes or until onion softens.
STIR in snow peas and bell pepper; stir fry 3 minutes or until tender-crisp. Add shrimp; stir fry 2 to 3 minutes or just until shrimp turn pink. Serve immediately.