Lightly spray 28 (1¼ x1-in.) molds in flexible plastic ice cube trays with nonstick spray; set aside.

Microwave baking chips in a medium microwave-safe bowl on HIGH at 15-second intervals until melted, stirring each time. Spoon chocolate into a disposable pastry bag. Cut off ¼-in. tip on end of pastry bag.

Pipe chocolate into prepared molds of ice cube trays, filling just until bottom of each mold is lightly coated with chocolate. Immediately press 3 marshmallows slightly into each section of chocolate. Drizzle with remaining melted chocolate.

Firmly tap filled ice cube trays on work surface a few times to compact ingredients. Garnish with banana chips and cashews. Sprinkle lightly with sea salt. Freeze for 10 minutes or until chocolate is set. Let stand at room temperature for 5 minutes. Pop chocolates out of ice cube trays before serving. If necessary, use the tip of paring knife to release. Store in covered container in refrigerator up to 1 week. Serve at room temperature.