Preheat an oven to 350 degrees F (175 degrees C).
Melt butter in a microwave-safe bowl in the microwave. Crush the ramen noodles into small pieces; stir the crushed noodles, almonds, and sesame seeds into the butter. Spread the mixture onto a baking sheet.
Bake in the preheated oven until golden brown and crunchy, 8 to 10 minutes; allow to cool completely.
Toss together the coleslaw mix and the green onion in a large bowl.
Whisk together the salad oil, vinegar, sugar, soy sauce, and reserved seasoning packets in a separate bowl; stir the noodle mixture into the dressing. Pour the dressing over the coleslaw mix and toss to coat.