1. Heat oven to 350 degrees. Spread the walnuts on a baking pan. Toast until fragrant, 7 to 10 minutes. Transfer nuts to a plate to cool.

2. Bring a large saucepan of salted water to a boil. Add the long beans, and cook until they are just tender and bright green, 1 to 2 minutes. Drain the beans in a colander, and pat them dry with a clean towel. Transfer to a large bowl, and set aside.

3. Heat the olive oil in a medium skillet over medium-low heat. Add the walnuts, fennel seeds, and cumin seeds, and cook, stirring continuously, until fragrant, 1 to 2 minutes. Remove from heat, pour mixture over the reserved beans, and toss to combine. Season to taste with salt and pepper, and serve.