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.