Cut salmon crossway into ½-inch wide strips and place in large Ziplock bag. Add vinegar, lemon juice, and zest, and fresh dill to bag. Seal tightly and shake to combine.
Marinate in the refrigerator for 20 to 30 minutes (do not marinate longer or the vinegar will start to cook the salmon).
Preheat gas or charcoal grill to medium heat. Remove salmon from bag and discard marinade.
Thread salmon pieces accordion-style (see pictures above for reference) onto skewers, alternating with zucchini slices. Sprinkle with salt and pepper.
Lightly oil grill with light olive oil or cooking spray to prevent sticking. Immediately place salmon kabobs on the grill. Cook uncovered for 5 to 7 minutes, rotating midway, until grill marks appear and fish is flaky when tested with a fork.
Squeeze a bit more lemon juice on top when serving.
Notes
Use wild-caught salmon for best quality and flavor.
No need to bring fish to room temperature before grilling. The thin pieces will cook fast and evenly.
Marinade ahead of time for extra flavor. Use a homemade salmon marinade with acidic properties, like vinegar and citrus, to add flavor. It also helps to tenderize fish by breaking down the proteins.
Don’t marinade seafood in an acidic marinade more than 30 minutes, or it will start to cook the meat. Unless you want to make shrimp ceviche tacos.
The trick is skewering them accordion-style so they stay on and don't fall into the grill. This also helps them cook evenly throughout, preventing uncooked or burnt areas.
Try alternating meat with other veggies such as bell pepper, onion, cherry tomatoes, or mushrooms.
Grill over medium heat creates nice sear marks without burning.