Heat 1//2 tablespoon olive oil in skillet over medium heat. Add garlic and cook for 30 seconds.
Add shrimp and cook until no longer translucent (they will be pink). Remove from heat and set aside.
Add remaining olive oil to pan. Add onion and squash.
Cook over medium heat, uncovered until squash begins to turn soft. If squash releases a lot of water, drain as much liquid as possible from pan and return to heat.
Cook another minute or two and then season to taste with garlic salt and pepper.
Divide squash between 4 dinner plates and top with cooked shrimp.