Tomato salad with purslane and mastiha vinaigrette

1 kg small tomatoes, or plum tomatoes or cherry tomatoes, preferably from Santorini
1 bunch of purslane (125g)
4 fresh spring onions, cleaned and cut into very thin slices
2 small cucumbers, cut into thin rounds
1 small yellow bell pepper, deseeded and finely chopped
1/3 cup finely chopped parsley
1/3 cup extra virgin olive oil
3-4 tbsp freshly squeezed lemon juice
½ tsp mastic powder or 3-4 drops Mastic oil from Chios
salt and pepper, to taste

Peel the tomatoes. If using cherry tomatoes, cut them in half. If using plum tomatoes, cut them into quarters. Clean the purslane and use only the leaves and tender shoots.
In a bowl, mix the tomatoes, purslane, onions, cucumber, pepper, and parsley.
Whisk together the olive oil, lemon juice, mastic powder or mastic oil, salt, and pepper.
Pour the vinaigrette over the salad, toss, and serve immediately.