Wash the potatoes. Cook in boiling salted water for 15-20 minutes. Then peel. In the meantime, peel the asparagus and cut off the woody ends. Pour into boiling salted water. Cook over medium heat for 15-20 minutes.
For the sauce, clean, wash, quarter and seed the tomatoes. Finely dice the flesh. Season lime juice with salt, pepper and sugar. Whip oil into it. Stir in diced tomatoes. Arrange asparagus and the marinade, potatoes and ham, generously sprinkled with chervil.
Serve garnished with slices of lime and tomato rose.