In a large bowl, whisk together the mayonnaise and half the vinegar. Add the sliced cabbage and as much of the chopped jalapeño pepper you would like. Season with salt and pepper, and toss to combine. Marinate for at least 10 minutes.
While the slaw marinates, [;lace the shrimp in a bowl and season with salt, pepper, and enough of the spice blend to coat.
Heat 1 tablespoon of oil in a medium nonstick pan on medium-high until hot. Add the seasoned shrimp and sliced poblano pepper in an even layer. Cook, without stirring, 2-3 minutes (or until shrimp are slightly opaque).
Toss and continue to cook for 1-2 minutes, or until pepper is softened and shrimp are cooked through. Turn off the heat and stir in remaining vinegar, season with salt and pepper if needed.