1. Bring a large pot of water to a boil. Place a large bowl of ice water next to the stove.
2. Add the green beans to the boiling water and cook until tender-crisp, about 4 minutes.
3. Transfer the beans with a slotted spoon to the ice water to cool. Drain well when completely cool. Stop at this step if you're blanching the beans in advance for later frying.
4. Heat oil in a large skillet over medium heat. Add garlic and cook, stirring constantly, until fragrant (30 seconds). Add the green beans, parsley, tarragon, salt, and pepper and cook, stirring, until heated through (1-3 minutes).