BLEND first 3 ingredients in blender until smooth.
HEAT 1 Tbsp. oil in large skillet on medium heat. Add garlic and onions; cook 5 min. or until tender. Remove from skillet. Heat remaining oil in skillet on medium-high heat. Add shrimp, in 2 batches; cook and stir 3 min. or until pink. Remove from skillet; cover to keep warm. Return garlic, onions and shrimp to skillet; stir in sauce mixture. Bring to boil; simmer on low heat 3 min. or until heated through.
SPOON over rice; serve topped with onions and sour cream.
