Rinse squash blossoms with cold water; pat dry with paper towels. Roughly chop the squash blossoms.
Heat olive oil in a medium skillet over medium-high heat. Saute onion and chiles for 2 to 3 minutes until it softens slightly.
Add the chopped tomatoes and saute for an additional 2 to 3 minutes; season with salt to taste.
Stir in the roughly chopped squash blossoms and saute just until they start to wilt; remove from heat.
Heat corn tortillas on a comal or skillet over medium-high heat until soft and pliable.
Spoon about 3 tablespoons of the filling into the center of warm corn tortillas.
Top with crumbled queso fresco. Serve with Chile de Molcajete, sour cream or guacamole.
