Cut the fish into several pieces and coarsely chop them with a knife.
In a small sauté pan, brown the sesame seeds over low heat for 5 minutes.
As soon as the seeds are cold, add them to the fish, salt and pepper, drizzle with olive oil.
When ready to serve, divide the tartare among plates (or verrines), place a few alfafa sprouts on top and at the same time present a slice of lemon.