Toast the slices of bread for approx. 10 mins. on the oven rack in an oven preheated to 180 °C (convection), remove and allow to cool a little.
Combine the cream cheese with the mineral water, mustard and pepper and spread over the toast.
Slice the eggs, place on top of the bread, top with the radishes and onion sprouts, season.
Mix the chives with the oil and drizzle over the egg carpaccio.