To cook the vegetables, heat a large frying pan over medium heat.
Add the olive oil then saute the vegetables until golden brown and cooked through. Add the garlic and oregano then fry for another minute or two.
Season to taste and remove from the heat. Allow to cool slightly.
Heat a large frying/griddle pan over high heat.
Place a tortilla in the pan then top with cheese and vegetables on one half of the tortilla. Fold over and press down on the quesadilla a little to ensure everything is glued together by the cheese.
Carefully flip the quesadilla to crisp up the other side.
Remove from the pan then continue with the remaining quesadillas.
Slice the quesidillas then serve with the guacamole and salsa.