1 Peel the onions and finely chop.
2 Immerse a sieve in a pot of boiling water. Drop in onions and cook for 30 seconds. Plunge sieve with onions into cold water and allow to cool. Drain well.
3 Finely chop pistachios. Peel orange with a knife so that all the pith is removed.
4 Cut orange into slices and coarsely chop. Juice the lime.
5 Rinse the tomatoes, remove stem ends, cut into quarters and remove the seeds. Finely chop tomatoes.
6 Mix tomatoes with diced onion, orange slices, 1 tablespoon lime juice, 2 tablespoons of olive oil and salt and pepper to taste.
7 Rinse basil, shake dry and coarsely chop the leaves. Add basil and pistachios to the salsa mixture. Set aside.
8 Rinse asparagus. Remove woody ends. If desired, peel the lower third of each spear.
9 Lay 5 spears of asparagus next to each other on the work surface. Spear asparagus together with 2 wooden skewers to facilitate turning and even browning. Repeat with remaining asparagus.
10 Brush grill pan and asparagus with the remaining olive oil.
11 In the grill pan, cook asparagus until al dente, 3-4 minutes on each side. Deglaze with vinegar. Season with salt and pepper. Serve with salsa.