Place the ground peppercorns on a small plate. Rub the rim of a glass with the lime wedge and dip the rim of the glass into the peppercorns to coat the rim.
Core and deseed the red pepper. Juice the pepper with the grapes.
Transfer the juice to a food processor or blender, add the ice cubes and process briefly until smooth.
Pour the juice into the prepared glass and serve immediately.