1 Rinse chicken, pat dry and cut into 2 cm (approximately 3/4-inch) cubes.
2 Peel the onions and cut into 2 cm (approximately 3/4-inch) pieces.
3 Thread the meat and onions alternately onto skewers.
4 Mix curry powder with 1 tablespoon oil and brush onto the skewers. Cover and let marinate for at least 1 hour in refrigerator.
5 Rinse tomatoes, cut out the stem ends and cut into slices. Place tomato slices on a plate.
6 In a bowl, mix balsamic vinegar with salt and pepper to taste. Stir in honey. Slowly whisk in the remaining oil.
7 Rinse chives and shake dry. Cut into thin rings and mix into the vinaigrette. Drizzle vinaigrette over the tomatoes.
8 Juice half a lemon. Cut avocado in half, remove the pit and scoop out the flesh from the shell.
9 Mash avocado with yogurt, 1 tablespoon lemon juice, and salt and pepper to taste.
10 Heat a grill pan. Season the skewers lightly with salt and grill for about 3-4 minutes on each side. Place skewers on the sliced tomatoes and serve with avocado-yogurt sauce.