Savory, Asian-inspired seafood, now in kebab form!
Soak eight 12-inch wooden skewers in water 15 minutes.
Stir together 1/4 cup cilantro, soy sauce, sesame oil, honey, sesame seeds, and black pepper in a big bowl. Set half of the resulting marinade aside. Add tuna to the remaining marinade in the bowl and toss to coat, then let it chill for 15 minutes.
Remove the tuna from the marinade. Place the marinade in a saucepan and boil it for 2 minutes. Thread tuna, shishito peppers, mushrooms, and eggplant onto skewers; make sure tuna is the starting and ending ingredient on each.
Heat a grill pan on medium-high and coat with cooking spray. Grill the skewers until they're charred, 3 to 4 minutes, making sure to turn them once. Brush with cooked marinade during last minute of grilling. Place the skewers on a plate and top them with the reserved marinade and remaining 1/4 cup cilantro.