¼ cup Dijon mustard
2 tablespoons French’s yellow mustard
1 tablespoon plus 1 teaspoon unseasoned rice vinegar
1 tablespoon plus 1 teaspoon mustard powder
¼ teaspoon cayenne pepper
2 cups coarsely chopped cooked cabbage (about 7 ounces)
1 cup (packed) coarsely chopped cooked corned beef (about 5 ounces)
½ cup coarsely chopped cooked carrots (about 3 ounces)
Kosher salt, freshly ground pepper
6 wonton wrappers
Neutral oil (for frying; about 4 cups)
A deep-fry thermometer