Turn your grill on high for at least 10 minutes to preheat.
For the chicken, in a medium bowl, stir together the soy sauce, coconut sugar, curry powder, salt, and red pepper flakes. Add the chicken and stir to coat evenly. Divide chicken pieces between your skewers (save any extra marinade in the bowl). Place on the grill and cook on medium-high, covered, for about 5-10 minutes or until deeply browned/charred.
Use a spatula to loosen the chicken from the grates and use tongs to flip them over. Brush any extra marinade from the bowl onto the skewers. Cook, covered, for 5 more minutes.
To make the dressing, in a small bowl or jar, whisk together the peanut butter, lime, soy, and sugar until a smooth thick paste forms (if peanut butter is cold, microwave for a few seconds to warm it up a bit so it mixes more easily). Whisk in the water until a smooth dressing/runny sauce forms.
In a large bowl, add the cabbage, cucumber, bell pepper, ½ of the scallions, and ½ of the dressing and toss to coat.
Serve the salad topped with the chicken, avocado, remaining scallions, peanuts, and drizzle the remaining dressing all over. Top with a squeeze of lime and sriracha (if using).