Preheat your grill on high. Add all of the ingredients to a blender (for the limes, just their juice - discard the limes themselves) Blend until smooth, taste and adjust salt level as desired.
Brush the shrimp with the marinade and let sit for a couple minutes. When ready to grill, oil the grill grate carefully with avocado oil. If using spray, work in light bursts to prevent flares and exploding the can.
Grill the shrimp on direct heat for 1-2 minutes each side until done. Brush more of the marinade on during the cooking process, and after. Serve immediately.