Littleneck Clams with New Potatoes and Spring Onions

INGREDIENTS

• 1 1/2 pounds small new potatoes, sliced 1/4" thick
• 3 tablespoons olive oil
• 4 ounces smoked Spanish chorizo, cut into 1/4" pieces
• 5 pounds littleneck clams, scrubbed
• 1 bunch spring onions or scallions, whites halved and sliced; greens sliced on a diagonal, divided
• 1 cup dry white wine (such as Sauvignon Blanc or Pinot Gris)
• 4 garlic cloves, thinly sliced
• Toasted bread (for serving)