4 baby bok choy (about 1 pound), split horizontally
2 tablespoons finely chopped chives
4 teaspoons reduced-sodium soy sauce
2 teaspoons lime juice
1 teaspoon lime zest
1/4 teaspoon sugar
1 teaspoon spicy sesame oil
Spicy sesame oil is available in the Asian section of most supermarkets, but you could also substitute a combination of regular sesame oil and red pepper flakes to taste.