Mix the lime juice, salt, pepper and the types of oil in a bowl. Halve the vanilla pod lengthways, scrape out the pulp and stir into the dressing. Cut the chives into fine rolls and add them.
Peel the asparagus and remove the woody ends. Then cut diagonally into very thin slices and mix thoroughly with the dressing. Finally, add sugar to taste as required (I like it a little sweeter and take about 2 tablespoon).