For Grilled Slaw: Heat grill to medium-high. Drizzle cabbage and onion wedges with 1 tablespoon oil and season with salt and pepper. Grill 5 minutes on each side or until lightly charred. Let cool 5 minutes or until cool enough to handle.
Whisk vinegar, mustard, dill, and remaining 1 tablespoon oil in large bowl. Roughly chop cabbage and onions. Add to bowl with dressing; mix gently.
For Meatballs: Reduce grill heat to medium. Combine frozen meatballs, beer, and caraway seed in small aluminum foil or other grill-safe pan. Simmer meatballs on grill 15 to 20 minutes or until heated through, stirring occasionally.
Meanwhile, drizzle peppers with oil and season with additional salt and pepper. Grill peppers 3-5 minutes on each side or until skin is lightly blistered. If desired, warm hot dog buns on grill.
Fill buns with drained meatballs and top with Grilled Slaw. Serve with mini peppers and any remaining slaw on the side.
To keep cabbage from falling apart, leave the core intact while grilling. If you’re having trouble keeping the vegetables from falling through the grill grates, use metal or wooden skewers to hold cabbage leaves and onion pieces together.
For an extra kick, substitute shishito peppers for the mini sweet peppers, or grill a jalapeño pepper with the cabbage and add to slaw.