How to Make It
Combine white and black sesame seeds in a large skillet. Cook over medium-low, stirring often, until fragrant and lightly toasted, 3 to 4 minutes. Remove from skillet, and set aside.
Heat 1/2 cup oil in skillet over medium until hot. Fry chiles in 2 batches, turning often and watching carefully to avoid burning, until just starting to crisp in spots but not blackened, 1 to 2 minutes. Transfer chiles to a medium bowl. Reduce heat to medium-low, and add garlic. Cook, stirring constantly, until lightly browned, 30 seconds to 1 minute and 30 seconds. Using a slotted spoon, transfer garlic to bowl with chiles.
Add pepitas to skillet. Cook over medium-low, stirring often, until mostly golden brown, 4 to 5 minutes. Drain and discard cooking oil.
Process chiles, garlic, 1/2 cup pepitas, and remaining 1/2 cup oil in a blender until mixture forms a coarse paste, about 20 seconds, stopping to scrape down sides as needed. Add remaining 1/4 cup pepitas, and pulse until coarsely broken, 5 to 8 times. Stir in toasted sesame seeds and salt.