Pan-Roasted Green Beans with Caramelized Onions

Name: Pan-Roasted Green Beans with Caramelized Onions
Ingredients: 1 pound green beans (trimmed); Large bowl of ice water; 1 tablespoon olive oil; 1 large sweet onion (like Vidalia, thinly sliced or coarsely chopped); Coarse salt and pepper to taste; Lemon zest as desired; 2 tablespoons toasted sliced almonds or toasted pine nuts