To prepare shrimp, combine first 5 ingredients in a bowl. Refrigerate 30 minutes. Heat oil in a large nonstick skillet over medium-high heat. Add shrimp; sauté 4 minutes or until done.
To prepare salsa, place tomatillos and next 9 ingredients (through serrano) in a food processor; process until smooth. Warm tortillas according to package directions. Divide shrimp evenly among tortillas. Top each with about 1/4 cup salsa; fold in half.