Thaw the shrimp, if frozen. Pat the shrimp dry and add it to a large bowl.
Mince the garlic. Peel and mince the ginger. In a small bowl, mix the soy sauce and 1 tablespoon of the sesame oil with the garlic, ginger, onion powder, and kosher salt. Toss the mixture with the shrimp.
In a large skillet, heat the remaining 1 tablespoon sesame oil on medium high heat. Add the shrimp and cook for 1 minute, then flip and cook additional 30 seconds. Add the Thai basil and turn continuously until basil is wilted and shrimp is fully cooked and opaque, about another 1 minute. Garnish with additional Thai basil leaves, if desired.