Preheat oven to 375°F, line baking sheet with parchment paper
Heat olive oil in large skillet over medium-high heat
Add diced onions, cook 2-3 minutes until softened
Add ground beef, cook 5-6 minutes until no pink remains
Drain excess grease from beef mixture
Add garlic, taco seasoning, and water, simmer 2-3 minutes
Remove from heat, let beef mixture cool 5 minutes
Separate crescent roll dough into triangles
Place 2 tablespoon beef mixture and cheese on wide end of each triangle
Roll up tightly from wide end, pinch seams to seal
Place seam-side down on prepared baking sheet
Beat egg, brush over tops, sprinkle with sesame seeds
Bake 12-15 minutes until golden brown and puffed
Let cool 3-4 minutes before serving