Gather ingredients and set grill to high heat.
Slice the onion into thick slices (1/2 inch or more) and push the center out.
Cover the onions completely with siracha sauce.
Wrap the onion with bacon strips (takes about 2 1/2 to 3). Secure with a long toothpick or skewer, so you can grab them on the grill without breaking the onion.
Mix together lime juice, mayo, and hot sauce and brush on top of onion rings.
Place onion rings on grill and cook for 45 minutes on each side.
Remove from grill and serve with the rest of the spice lime mayo.