Cut your steak into large pieces (around 1 1/4 - 1 1/2 inches). Try to keep them uniform in size so they'll cook in the same amount of time.
Add your steak, coconut aminos (or soy sauce), and olive oil to a gallon ziploc bag. Squeeze out excess air and zip closed. Use your fingers to massage the marinade evenly around the steak. Let sit for at least 30 minutes, flipping the bag over occasionally.
Cut the tops off your peppers. Scoop out any seeds and discard along with the tops. Slice the peppers into evenly sized chunks.
Remove the top and outside of the pineapple. Remove the core. Cut the flesh into large chunks.
Thread your marinated steak, peppers, and pineapple chunks onto skewers.
Place on a baking sheet and drizzle excess marinade from the bag over the kabobs so that your veggies also have a nice coat. (The olive oil in the marinade will help the veggies get a beautiful char.)
Sprinkle with salt and pepper.
Heat grill to medium-high heat. Place kabobs on the grill so they're not touching. Grill for 3-5 minutes. Flip. Grill for another 3-5 minutes. Remove when you've achieved your desired doneness.