Heat a skillet over medium heat. Add Impossible Burger and cook until fully browned, about 10 minutes. Mix in 1/2 of the chopped onion, minced garlic, salt, and cumin. Cook and stir over low heat until fragrant, about 5 minutes.
Spray a separate skillet with nonstick spray and warm flour tortillas over low heat until lightly toasted, about 30 seconds per side.
Assemble your tacos with the filling, remaining raw onion, tomato, queso fresco, and cilantro. Squeeze some lime juice over the tacos and serve remaining wedges alongside.