In medium bowl, toss shrimp, sriracha, lime juice and zest; cover and let stand 15 minutes
In large skillet, heat oil over medium-high heat. Add shrimp mixture; cook 5 minutes or until shrimp turn opaque throughout and internal temperature reaches 145°, turning once.
Fill tortillas with cabbage, onion, shrimp, avocado, cilantro, sriracha, if desired, and sour cream.