Halve the tomatoes and peel and halve the onion, then place in a roasting tray with the unpeeled garlic cloves. Season, drizzle with 1 tablespoon of oil and roast for 30 minutes, or until soft. Transfer to a plate and allow to cool. Peel the garlic.
Place the tamarind pulp in a small bowl, cover with boiling water and soak for 15 minutes (if using paste, omit this step).
Place the chillies in a bowl. Cover with boiling water and soak for 15 minutes. Drain, reserving the liquid.
Place the chillies, garlic, half the roasted onion, the tomatoes, 3 tablespoons of oil, 1 tablespoon of sea salt and some freshly ground black pepper in a food processor and blend to a thick paste.
Add the tamarind pulp and liquid (or the paste), then 6 tablespoons of the chilli liquid and blend briefly again to combine. Transfer the mixture to a large non-reactive bowl.
Slice, then place the squid in the marinade, cover with clingfilm and marinate for 3 to 4 hours in the fridge.
Preheat a barbecue or cast-iron griddle pan to a medium heat.
Remove the squid from the fridge, shake off excess marinade and cook, turning, for 10 to 15 minutes, or until tender and beginning to blacken.
For the salsa, cook the pineapple on a barbecue or cast-iron griddle pan on medium heat, turning occasionally, for 5 to 7 minutes or until tender and blackening.
Transfer to a food processor, pick, finely chop and add the mint, along with the remaining roasted onion and blitz to a chunky paste. Stir through the lime juice.
Divide the squid among serving plates and serve with the pineapple salsa and a squeeze of fresh lime.