There is a reason we refer to this as ‘Sweet Potato Crack’.

Ingredients
2 medium cucumbers
1/4 cup rice wine vinegar
1 teaspoon sugar
1/4 teaspoon salt
2 tablespoons sesme seeds, toasted
Directions
Combine vinegar, sugar in salt in medium bowl and stir to dissolve.
Wash cucumbers thoroughly, then slice as thin as possible. Add cucumber slices and toasted sesame seeds to vinegar mix; toss well to combine.
Serve immediately.

These aren’t quite the same as ‘real’ onion rings, but they’ve got that chewy/crunchy flavor and texture and are quite satisfying.