Boil a pot of water over high heat. Add green beans, and cook for 3-5 minutes or until tender crisp. Remove from water and immerse in ice water immediately to stop cooking.
Heat a saucepan over medium heat. Add bacon, and cook until crispy. Remove bacon, reserving bacon grease.
Reduce heat to low, add butter. Add in almonds, and cook until golden brown, about 4 minutes. Add garlic and cook until fragrant, about another minute.
Add lemon juice, then add green beans. Stir in salt (if desired), pepper, and chili flakes to taste. Cook until heated.
Garnish with fresh lemon zest when serving.
