Here's a recipe for chicken hekka from the Ono Recipes.

When I was a small kid, my mom would use cut up chicken wings and use those instead of the chicken breast. It was cheaper and somehow dark meat tastes better. She would sometimes also omit the watercress. Basically, you can throw whatever veggies you have around.

To me, the basic components of hekka are the chicken, the shoyu-based sauce, and the cellophane noodles. Hope that helps. Now you're making me hungry for hekka too!