Toast nuts and seeds in a cast-iron frying pan on medium heat OR in the oven -- until golden-brown; set aside to cool.
Break ramen noodles into small pieces; set aside until just before serving time.
In a large bowl, combine coleslaw, lettuce, onion and crab.
Mix dressing ingredients and the seasoning packet in a pint jar or other container with a lid; stir or shake until sugar is mostly dissolved.
AT SERVING TIME: add nuts and noodles to the salad; toss well. Drizzle dressing over the salad and toss to coat. Serve immediately.
LEFTOVERS: This salad is really good the next day too, but the ramen will have lost its crunchiness -- so ADD another packet of broken ramen noodles.
LARGE FAMILY/POTLUCK OPTION: Add two packets of ramen noodles to stretch it a bit further.
SUBSTITUTIONS: Switch out the crab for some cooked chicken breast chunks or even shrimp! Add a few tablespoons of finely minced green Bell peppers (orange, red, yellow, too). Use scallions instead of a large onion.