Combine the dried chiles with the olive and canola oils in a small saucepan. Warm the mixture slowly over medium-low heat until the chiles become aromatic, being careful not to let them burn. Remove from the heat and allow the oil to cool to room temperature. Meanwhile, toast the coriander, cumin, white sesame, and black sesame seeds in a dry skillet over medium heat, stirring frequently until fragrant and golden. Let the toasted seeds cool slightly.

Transfer the cooled oil mixture, toasted seeds, and garlic (if using) to a high-powered blender such as a Vitamix. Blend until mostly smooth but still slightly textured. Add the lime juice and salt to taste, then blend briefly to combine. Transfer to a clean jar and refrigerate. Stir or shake before using. The salsa will keep for up to two weeks.