To make the tamarind water, soak the tamarind paste in boiling water for 5 minutes breaking up any chunks with a spoon. Set aside until cool enough to handle. Pass the mixture through a sieve to get the tamarind water.
To make the tamarind marinade, in a bowl whisk together tamarind water, fish sauce, sugar, garlic, and freshly ground pepper until well combined.
In a container large enough to hold the salmon, add the marinade and place the fish meat side down, cover, and marinate for at least 4 hours or overnight.
When ready to cook the salmon, spray the bottom of the air fryer basket with the olive oil spray.
Put a piece of foil underneath the salmon and carefully lower salmon into the basket of the air fryer.
Attach the air fryer lid. Press the Air Fry button and set the temperature for 375 degrees F for 12 minutes then press Start.
Remove salmon from the basket immediately or it will continue to cook. Discard foil and transfer fish to a serving plate.
To make the sticky tamarind sauce, in a small saucepan, combine tamarind water, fish sauce, and sugar and cook on med-high heat for 10-12 minutes until the sauce thickens. Season with additional fish sauce and sugar to taste. Add sliced chilis. Set aside.
To make the fried shallots, add oil to a small frying pan over low heat. Add the dried shallots and cook until light golden, about 3 minutes.
When ready to serve, drizzle the sticky tamarind sauce over salmon, top with fried shallots, roasted peanuts, scallion, and cilantro.
Serve immediately with rice, steamed vegetables, and remaining tamarind sauce.