To make the salsa, add all of the ingredients (reserving some of the chopped echalion to garnish) to a food processor and pulse to a chunky salsa.
Toss the halloumi slices and shallots with the olive oil, cumin, paprika and seasoning. Heat a griddle pan on a medium high heat and cook the halloumi and shallots until charred and cooked through.
While they are cooking, make the guacamole. Slice and destone the avocados. Add to a bowl with the rest of the ingredients and roughly mash with a fork.
Warm the tortillas through in a dry frying pan.
To assemble the tacos, spread each tortilla with a tablespoon of guacamole. Add a few halloumi slices and an echalion half. Top with a generous spoon of the green salsa, and some finely chopped echalion.