For BBQ sauce, combine ingredients in a medium saucepot and simmer over medium-low heat.
Set up a breading station for the chicken: In a shallow dish, combine rice flour and corn starch; in another, beat the eggs; in a third, place Panko and season with sugar, pepper, salt and garlic powder. Coat each piece of chicken first in the flour, then the egg and lastly the breadcrumb mixture.
If frying, heat an inch of oil over medium-high heat in a deep-sided skillet. Add chicken and fry 7-8 minutes to deep golden, turning occasionally.
To oven-fry, place chicken on a nonstick baking sheet, spray with cooking spray and bake at 425°F to deep golden.
For the slaw, combine avocado with lime juice, sour cream or Greek yogurt, garlic, shallot, herbs, celery salt, and sugar in a food processor. Process until smooth. Add cabbage, carrots and poppy seeds to a large serving bowl and pour dressing over; toss to coat.
Dip chicken in BBQ sauce and place on roll bottoms. Top with pickles and slaw, set bun tops in place and serve.
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