Place chicken strips and cornstarch in a large resealable plastic bag. Shake to coat.

Heat vegetable oil in a large skillet over medium-high heat. Add chicken and cook until golden brown on the outside and juices run clear, about 5 minutes on each side. Transfer to a paper towel-lined plate.

Whisk together garlic, ginger puree, Sriracha, sesame oil, rice vinegar, brown sugar, and soy sauce. Add mixture to the skillet and bring to a boil. Reduce heat and simmer until sauce has thickened, about 3 minutes.

Return chicken to the skillet. Add green onions and toss to coat. Cook over medium-high until heated through, about 2 minutes. Serve immediately.