Bring 1 inch of water to a boil in a high-sided saute pan. If using fresh beans, cut them lengthwise while you wait for the water to boil.
Add salt and green beans to boiling water and cook until just tender. Drain beans and rinse under cold water to stop the cooking. Return the skillet to medium heat and add the butter. When butter is melted, add the almonds and cook until golden brown.
Return the green beans to the pan, along with the juice of 1/2 a lemon, add salt and pepper, to taste. When warmed through, top with fried onions.