Bring 1 inch of water to a boil in a deep sauté pan. If using fresh beans, cut them lengthwise while you wait for the water to boil.
Add salt and the green beans to the boiling water and cook until just tender. Drain the beans and rinse them under cold water to stop the cooking. Return the skillet to medium heat and add the butter. When the butter is melted, add the almonds and cook until golden brown.
Return the green beans to the pan, along with the lemon juice; add salt and pepper, to taste. When warmed through, top with the fried onions.