Line a baking tray with non-stick baking paper. Place melts in a heatproof microwavesafe bowl. Heat, uncovered, in 1 minute bursts on HIGH (100%) power, stirring every minute with a metal spoon or until smooth. Spread hundreds and thousands over a plate.
Using a clean, dry pastry brush, brush a thin layer of chocolate over half of 1 grissini. Immediately roll chocolate half in hundreds and thousands (sprinkle hundreds and thousands over any uncovered areas).
Place grissini on tray. Repeat with remaining ingredients. Allow to set.