Wipe outside of chilis with damp paper towel to remove any dust. Heat large deep skillet on medium-high heat. Toast chilis in hot pan until fragrant, about 10 seconds per side, working in batches as needed. Toast cumin seeds in same skillet until fragrant, about 10 seconds. Remove from skillet immediately.
Place water, garlic and toasted chilis in medium saucepan. Bring to boil. Cover and simmer on medium-low heat until chilis are softened, about 10 minutes. Remove from heat.
Transfer chilis, garlic and cooking liquid to blender container. Add cilantro, cumin, oregano and salt. With center part of cover removed to allow steam to escape, puree on high speed until smooth.
Heat oil in medium saucepan on medium-high heat. Carefully add chili mixture to skillet (hot oil may splatter, reduce heat slightly if needed!). Cook and stir until slightly thickened, about 3 to 5 minutes. Serve salsa over grilled flank steak or with fresh tortilla chips, or use to top tacos, enchiladas, scrambled eggs or cactus salad.