Preheat oven to 400 degrees F. Lightly coat a shallow baking pan with nonstick cooking spray. Rinse beans in colander; shake, allowing some water to remain on beans. Place wet beans into prepared pan; drizzle with 1 Tbsp. of the oil. Toss to coat; spread in an even layer. Sprinkle with 1/2 tsp. kosher salt. Roast, uncovered, 20 minutes or until tender and slightly charred, stirring once.
Meanwhile, heat remaining 1 Tbsp. oil in large skillet over medium-high heat. Add garlic; stir 30 seconds. Add panko; stir about 2 minutes or until just golden. Add zest, tarragon, 1/2 tsp. kosher salt, and black pepper; stir to combine. Toss panko mixture with roasted green beans.