I'm gonna start with nukes, because focused attacks like lasers wouldn't have the glassing effect you're looking for.
There are a few scenarios.
If you set off enough nukes to cover the surface all at once, it would blow most of the atmosphere into space, vaporize the top three meters of ocean, and surround the planet with a layer of hot gas. I can't calculate exact time scales, but for the first few weeks, the surface would get pelted by silicates and metals freezing and falling like ash. In a period of years, most of the carbon-based ash would fall out. In a period of decades, the water would precipitate out, then freeze. Without the original atmosphere acting like a blanket, the planet would turn into an airless, frozen husk covered in ice.
If you set off the bombs like a wave, you could keep most of the air on the planet. A two thousand degree blast of air would scour the surface at hundreds of miles per hour, preceding the bombs that will keep it moving. The force of the wind would scrape the surface clean before the bombs melted the underlying rock. The wind would rip the rough parts off of mountain ranges. It would vaporize the top layer of ocean and choke what's left of the oceans with debris. This model would take even longer to cool off, but in this case the heat would dissociate the water's elements, and you'd launch a large amount of dissociated hydrogen into space. The dissociated oxygen would combine with carbon, creating a Venusian greenhouse.
All said, you're going to have to spend tens of thousands of years re-terraforming the planet either way.