If making homemade tostadas, pre-heat the oven to 400 degrees.
Cook the onions and ground beef in a skillet over medium heat until browned. Drain the excess fat, then stir in the seasonings and chopped chile pepper.
Add to the beef mixture and cook until the zucchini is tender. Season with salt, pepper and chicken bouillon to taste.
While the beef cooks, arrange the tortillas on a baking sheet and lightly spray both sides with olive oil. Bake in the oven for about 7 minutes per side, until golden and crisp.
Combine in a small bowl. Set aside.
Spoon the beef mixture onto the tostadas. Top with cheese, coleslaw, and salsa.